View source for Hydrogen peroxide

{{Short description|Chemical compound}}
{{Use dmy dates|date=October 2020}}
{{chembox
| Verifiedimages = changed
| Watchedfields = changed
| verifiedrevid = 477315142
| Name = Hydrogen peroxide
| ImageFile = Wasserstoffperoxid.svg
| ImageName = Structural formula of hydrogen peroxide
| ImageFile_Ref = {{chemboximage|correct|??}}
| ImageFileL1 = Hydrogen-peroxide-3D-balls.png
| ImageFileR1 = Hydrogen-peroxide-3D-vdW.png
| ImageNameR1 = Space filling model of the hydrogen peroxide molecule
| ImageCaptionR1 = {{legend|red|Oxygen, O}}{{legend|white|Hydrogen, H}}
| IUPACName = Hydrogen peroxide
|SystematicName= Peroxol
| OtherNames = Dioxidane<br/>Oxidanyl<br/>Perhydroxic acid<br/>0-hydroxyol<br/>Oxygenated water<br/>Peroxaan
| Section1 = {{Chembox Identifiers
|UNII_Ref = {{fdacite|correct|FDA}}
|UNII = BBX060AN9V
|KEGG_Ref = {{keggcite|correct|kegg}}
|KEGG = D00008
|InChI = 1/H2O2/c1-2/h1-2H
|ChEBI_Ref = {{ebicite|correct|EBI}}
|ChEBI = 16240
|SMILES = OO
|InChIKey = MHAJPDPJQMAIIY-UHFFFAOYAL
|ChEMBL_Ref = {{ebicite|correct|EBI}}
|ChEMBL = 71595
|StdInChI_Ref = {{stdinchicite|correct|chemspider}}
|StdInChI = 1S/H2O2/c1-2/h1-2H
|StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
|StdInChIKey = MHAJPDPJQMAIIY-UHFFFAOYSA-N
|CASNo = 7722-84-1
|CASNo_Ref = {{cascite|correct|CAS}}
|ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
|ChemSpiderID = 763
|PubChem = 784
|IUPHAR_ligand = 2448
|RTECS = MX0900000 (>90% soln.)<br/>MX0887000 (>30% soln.)
|EINECS = 231-765-0
|UNNumber = 2015 (>60% soln.)<br/>2014 (20–60% soln.)<br/>2984 (8–20% soln.)
}}
| Section2 = {{Chembox Properties
| H=2 |O=2
|Appearance = Very light blue liquid
|Odor = slightly sharp
|Density = 1.11&nbsp;g/cm<sup>3</sup> (20&nbsp;°C, 30% (w/w) solution)<ref>{{cite journal| vauthors = Easton MF, Mitchell AG, Wynne-Jones WF |title=The behaviour of mixtures of hydrogen peroxide and water. Part 1.—Determination of the densities of mixtures of hydrogen peroxide and water|journal=Transactions of the Faraday Society|date=1952|volume=48|pages=796–801|doi=10.1039/TF9524800796|s2cid=96669623}}</ref><br/>1.450&nbsp;g/cm<sup>3</sup> (20&nbsp;°C, pure)
|Solubility = [[Miscible]]
|SolubleOther = soluble in [[diethyl ether|ether]], [[ethanol|alcohol]]<br/> insoluble in petroleum ether
|MeltingPtC = -0.43
|BoilingPtC = 150.2
|BoilingPt_notes = (decomposes)
|pKa = 11.75
|RefractIndex = 1.4061
|Viscosity = 1.245&nbsp;c[[Poise (unit)|P]] (20&nbsp;°C)
|Dipole = 2.26&nbsp;[[Debye|D]]
|VaporPressure = 5 mmHg (30&nbsp;°C)<ref name="PGCH"/>
|MagSus = −17.7·10<sup>−6</sup> cm<sup>3</sup>/mol
|LogP = −0.43<ref name="chemsrc">{{Cite web|url=https://www.chemsrc.com/en/cas/7722-84-1_584358.html|title=Hydrogen peroxide|website=www.chemsrc.com|access-date=3 May 2018|archive-date=17 March 2020|archive-url=https://web.archive.org/web/20200317161038/https://www.chemsrc.com/en/cas/7722-84-1_584358.html|url-status=live}}</ref>
}}
| Section3 = {{Chembox Thermochemistry
|DeltaHf = −187.80 kJ/mol
|HeatCapacity = 1.267 J/(g·K) (gas)<br/> 2.619 J/(g·K) (liquid)
}}
| Section4 = {{Chembox Pharmacology
|ATCCode_prefix = A01
|ATCCode_suffix = AB02
|ATC_Supplemental = {{ATC|D08|AX01}}, {{ATC|D11|AX25}}, {{ATC|S02|AA06}}
}}
| Section5 = {{Chembox Hazards
|ExternalSDS = [https://www.inchem.org/documents/icsc/icsc/eics0164.htm ICSC 0164 (>60% soln.)]
|GHSPictograms={{GHS03}}{{GHS05}}{{GHS07}}
|GHSSignalWord=danger
|HPhrases = {{H-phrases|271|302|314|332|335|412}}
|PPhrases = {{P-phrases|280|305+351+338|310}}
|NFPA-H = 3
|NFPA-F = 0
|NFPA-R = 3
|NFPA-S = OX
|FlashPt = Non-flammable
|LD50 = 1518 mg/kg{{citation needed|date=July 2015}}<br/>2000 mg/kg (oral, mouse)<ref name="IDLH">{{IDLH|772841|Hydrogen peroxide}}</ref>
|IDLH = 75 ppm<ref name="PGCH">{{PGCH|0335}}</ref>
|REL = TWA 1 ppm (1.4 mg/m<sup>3</sup>)<ref name="PGCH"/>
|PEL = TWA 1 ppm (1.4 mg/m<sup>3</sup>)<ref name="PGCH"/>
|LC50 = 1418 ppm (rat, 4 hr)<ref name="IDLH"/>
|LCLo = 227 ppm (mouse)<ref name="IDLH"/>
}}
| Section6 = {{Chembox Related
|OtherCompounds = [[water (molecule)|Water]]<br/>[[Ozone]]<br/>[[Hydrazine]]<br/>[[Hydrogen disulfide]]<br/>[[Dioxygen difluoride]]
}}
}}
'''Hydrogen peroxide''' is a [[chemical compound]] with the formula {{chem2|auto=yes|H2O2}}. In its pure form, it is a very pale blue<ref name=House>{{cite book |vauthors = Housecroft CE, Sharpe AG |title=Inorganic Chemistry |date=2005 |publisher=Pearson Prentice-Hall |isbn=0130-39913-2 |pages=443–44 |edition=2nd}}</ref> [[liquid]] that is slightly more [[viscosity|viscous]] than [[Properties of water|water]]. It is used as an [[oxidizer]], [[bleach]]ing agent, and [[antiseptic]], usually as a dilute solution (3%–6% by weight) in water for consumer use and in higher concentrations for industrial use. Concentrated hydrogen peroxide, or "[[high-test peroxide]]", decomposes explosively when heated and has been used as both a [[monopropellant]] and an oxidizer in [[rocket]]ry.<ref>{{cite book |vauthors = Hill CN |date=2001 |title=A Vertical Empire: The History of the UK Rocket launch and Space Programme, 1950–1971 |publisher=Imperial College Press |isbn=978-1-86094-268-6 |url=https://books.google.com/books?id=AzoCJfTmRDsC |access-date=24 August 2020 |archive-date=13 April 2021 |archive-url=https://web.archive.org/web/20210413211242/https://books.google.com/books?id=AzoCJfTmRDsC |url-status=live}}</ref>

Hydrogen peroxide is a [[reactive oxygen species]] and the simplest [[peroxide]], a compound having an oxygen–oxygen [[single bond]]. It decomposes slowly into water and elemental [[oxygen]] when exposed to light, and rapidly in the presence of organic or reactive compounds. It is typically stored with a [[Stabilizer (chemistry)|stabilizer]] in a weakly acidic solution in an opaque bottle. Hydrogen peroxide is found in biological systems including the human body. Enzymes that use or decompose hydrogen peroxide are classified as [[peroxidases]].

==Properties==
The boiling point of {{chem2|H2O2}} has been extrapolated as being {{Convert|150.2|C||abbr=}}, approximately {{Convert|50|C-change||abbr=}} higher than water. In practice, hydrogen peroxide will undergo potentially explosive [[thermal decomposition]] if heated to this temperature. It may be safely distilled at lower temperatures under reduced pressure.<ref>{{cite book |veditors = Brauer G |others=Translation editing by Reed F. |date=1963 |title=Handbook of preparative inorganic chemistry |edition=2nd |volume=1 |publisher=Academic Press |location=New York|isbn=978-0-12-126601-1 |page=140}}</ref>

Hydrogen peroxide forms stable [[adduct]]s with [[urea]] ([[hydrogen peroxide–urea]]), sodium carbonate ([[sodium percarbonate]]) and other compounds.<ref>{{Cite journal| vauthors = Chernyshov IY, Vener MV, Prikhodchenko PV, Medvedev AG, Lev O, Churakov AV |date=2017-01-04|title=Peroxosolvates: Formation Criteria, H2O2 Hydrogen Bonding, and Isomorphism with the Corresponding Hydrates|journal=Crystal Growth & Design|volume=17|issue=1|pages=214–220|doi=10.1021/acs.cgd.6b01449|issn=1528-7483}}</ref> An acid-base adduct with [[triphenylphosphine oxide]] is a useful "carrier" for {{chem2|H2O2}} in some reactions.

===Structure===
{{multiple image
| direction = hoizontal
| align = left
| header =
| width = 210
| image1 = H2O2 gas structure.svg
| alt1 = O−O bond length = 147.4 pm<br/>O−H bond length = 95.0 pm
| caption1 = Structure and dimensions of {{chem2|H2O2}} in the gas phase
| image2 = H2O2 solid structure.svg
| alt2 = O−O bond length = 145.8 pm<br/>O−H bond length = 98.8 pm
| caption2 = Structure and dimensions of {{chem2|H2O2}} in the solid (crystalline) phase
}}

Hydrogen peroxide ({{chem2|H2O2}}) is a nonplanar molecule with (twisted) C<sub>2</sub> [[Molecular symmetry#Common point groups|symmetry]]; this was first shown by [[Paul-Antoine Giguère]] in 1950 using [[infrared spectroscopy]].<ref>{{cite journal |vauthors = Giguère PA |date=1950 |title=The Infra-Red Spectrum of Hydrogen Peroxide |journal=Journal of Chemical Physics |volume=18 |issue=1 |page=88 |doi=10.1063/1.1747464 |url=https://authors.library.caltech.edu/11457/1/GIGjcp50.pdf |access-date=31 December 2018 |archive-url=https://web.archive.org/web/20171202122026/https://authors.library.caltech.edu/11457/1/GIGjcp50.pdf |archive-date=2 December 2017 |url-status=live |bibcode=1950JChPh..18...88G}}</ref><ref>{{cite journal |vauthors = Giguère PA |date=1983 |title=Molecular association and structure of hydrogen peroxide |journal=[[Journal of Chemical Education]] |volume=60 |issue=5 |pages=399–401 |doi=10.1021/ed060p399 |bibcode=1983JChEd..60..399G}}</ref> Although the O−O bond is a [[single bond]], the molecule has a relatively high [[rotational barrier]] of 386&nbsp;[[inverse centimeter|cm<sup>−1</sup>]] (4.62&nbsp;[[Kilojoule|kJ]]/[[Mole (chemistry)|mol]]) for rotation between [[enantiomer]]s via the [[Cis–trans isomerism|''trans'']] configuration, and 2460&nbsp;cm<sup>−1</sup> (29.4&nbsp;kJ/mol) via the [[Cis–trans isomerism|''cis'']] configuration.<ref name="Hunt1965">{{cite journal |vauthors = Hunt RH, Leacock RA, Peters CW, Hecht KT |date=1965 |title=Internal-Rotation in Hydrogen Peroxide: The Far-Infrared Spectrum and the Determination of the Hindering Potential |journal=The Journal of Chemical Physics |bibcode=1965JChPh..42.1931H |doi=10.1063/1.1696228 |volume=42 |issue=6 |page=1931 |url=https://deepblue.lib.umich.edu/bitstream/handle/2027.42/71115/JCPSA6-42-6-1931-1.pdf?sequence=2 |hdl=2027.42/71115 |access-date=9 April 2014 |archive-url=https://web.archive.org/web/20140409085232/https://deepblue.lib.umich.edu/bitstream/handle/2027.42/71115/JCPSA6-42-6-1931-1.pdf?sequence=2 |archive-date=9 April 2014 |url-status=live |hdl-access=free}}</ref> These barriers are proposed to be due to [[Repulsion (chemistry)|repulsion]] between the [[lone pair]]s of the adjacent oxygen atoms and dipolar effects between the two O–H bonds. For comparison, the rotational barrier for [[ethane]] is 1040&nbsp;cm<sup>−1</sup> (12.4&nbsp;kJ/mol).

The approximately 100° [[dihedral angle]] between the two O–H bonds makes the molecule [[chiral]]. It is the smallest and simplest molecule to exhibit [[enantiomer]]ism. It has been proposed that the [[stereospecific|enantiospecific]] interactions of one rather than the other may have led to amplification of one enantiomeric form of [[ribonucleic acid]]s and therefore an origin of [[homochirality]] in an [[RNA world]].<ref>{{cite journal |vauthors = Ball R, Brindley J |title = The Life Story of Hydrogen Peroxide III: Chirality and Physical Effects at the Dawn of Life |journal = Origins of Life and Evolution of the Biosphere |volume = 46 |issue = 1 |pages = 81–93 |date = March 2016 |pmid = 26399407 |doi = 10.1007/s11084-015-9465-y |s2cid = 9564774 |bibcode = 2016OLEB...46...81B}}</ref>

The molecular structures of gaseous and [[crystalline]] {{chem2|H2O2}} are significantly different. This difference is attributed to the effects of [[hydrogen bonding]], which is absent in the gaseous state.<ref>{{cite book |vauthors = Dougherty DA, Anslyn EV |date=2005 |title=Modern Physical Organic Chemistry |publisher=University Science |isbn=978-1-891389-31-3 |page=122}}</ref> Crystals of {{chem2|H2O2}} are [[tetragonal]] with the [[space group]] ''D''{{su|b=4|p=4}} or ''P''4<sub>1</sub>2<sub>1</sub>2.<ref>{{cite journal |vauthors = Abrahams SC, Collin RL, Lipscomb WN |date=1 January 1951|title=The crystal structure of hydrogen peroxide |journal=Acta Crystallographica |doi=10.1107/S0365110X51000039 |volume=4 |issue=1 |pages=15–20|bibcode=1951AcCry...4...15A |doi-access=free}}</ref>

===Aqueous solutions===
In [[aqueous solution]]s, hydrogen peroxide forms a [[eutectic]] mixture, exhibiting [[freezing-point depression]] down as low as -56&nbsp;°C; pure water has a freezing point of 0&nbsp;°C and pure hydrogen peroxide of -0.43&nbsp;°C. The boiling point of the same mixtures is also depressed in relation with the mean of both boiling points (125.1&nbsp;°C). It occurs at 114&nbsp;°C. This boiling point is 14&nbsp;°C greater than that of pure water and 36.2&nbsp;°C less than that of pure hydrogen peroxide.<ref>{{cite web|url=https://www.h2o2.com/intro/FMC_MSDS_40_to_60.pdf|title=Hydrogen Peroxide Technical Library|access-date=3 March 2016|archive-url=https://web.archive.org/web/20091229052623/https://www.h2o2.com/intro/FMC_MSDS_40_to_60.pdf|archive-date=29 December 2009|url-status=dead}}</ref>

<li style="display: inline-table; vertical-align:top;>
[[File:Phase diagram hydrogen peroxide water.svg|423px|thumb|[[Phase diagram]] of {{chem2|H2O2}} and water: Area above blue line is liquid. Dotted lines separate solid–liquid phases from solid–solid phases.]]
</li>

<li style="display: inline-table; vertical-align:top;>
{| class="wikitable"
|+ Density of aqueous solution of {{chem2|H2O2}}
|-
! {{chem2|H2O2}} ([[w/w]]) !! Density<br>(g/cm<sup>3</sup>) !! Temp.<br>(°C)
|-
| 3% || 1.0095 || 15
|-
| 27% || 1.10 || 20
|-
| 35% || 1.13 || 20
|-
| 50% || 1.20 || 20
|-
| 70% || 1.29 || 20
|-
| 75% || 1.33 || 20
|-
| 96% || 1.42 || 20
|-
| 98% || 1.43 || 20
|-
| 100% || 1.45 || 20
|}
</li>

Hydrogen peroxide is most commonly available as a solution in water. For consumers, it is usually available from pharmacies at 3 and 6 [[wt%]] concentrations. The concentrations are sometimes described in terms of the volume of oxygen gas generated; one milliliter of a 20-volume solution generates twenty milliliters of oxygen gas when completely decomposed. For laboratory use, 30 wt% solutions are most common. Commercial grades from 70% to 98% are also available, but due to the potential of solutions of more than 68% hydrogen peroxide to be converted entirely to steam and oxygen (with the temperature of the steam increasing as the concentration increases above 68%) these grades are potentially far more hazardous and require special care in dedicated storage areas. Buyers must typically allow inspection by commercial manufacturers.

===Comparison with analogues===
Hydrogen peroxide has several structural analogues with {{chem2|H_{''m''}X\sXH_{''n''}|}} bonding arrangements (water also shown for comparison). It has the highest (theoretical) boiling point of this series (X = O, S, N, P). Its melting point is also fairly high, being comparable to that of [[hydrazine]] and water, with only [[hydroxylamine]] crystallising significantly more readily, indicative of particularly strong hydrogen bonding. [[Diphosphane]] and [[hydrogen disulfide]] exhibit only weak hydrogen bonding and have little chemical similarity to hydrogen peroxide. Structurally, the analogues all adopt similar skewed structures, due to repulsion between adjacent [[lone pair]]s.

{| class="wikitable sortable"
|+ Properties of {{chem2|H2O2}} and its analogues<br/>Values marked * are extrapolated
|-
! Name !! Formula !! [[Molar mass]]<br>(g/mol) !! Melting<br>point (°C) !! Boiling<br>point (°C)
|-
| [[Properties of water|Water]] || HOH || 18.02 || 0.00 || 99.98
|-
| Hydrogen peroxide || HOOH || 34.01 || −0.43 || 150.2*
|-
| [[Hydrogen disulfide]] || HSSH || 66.15 || −89.6 || 70.7
|-
| [[Hydrazine]] || H<sub>2</sub>NNH<sub>2</sub> || 32.05 || 2 || 114
|-
| [[Hydroxylamine]] || NH<sub>2</sub>OH || 33.03 || 33 || 58*
|-
| [[Diphosphane]] || H<sub>2</sub>PPH<sub>2</sub> || 65.98 || −99 || 63.5*
|}

==Natural occurrence==
Hydrogen peroxide is produced by various biological processes mediated by [[enzyme]]s.

Hydrogen peroxide has been detected in surface water, in groundwater, and in the [[atmosphere]]. It can also form when water is exposed to UV light.<ref>{{Cite journal |last1=Li |first1=Juan |last2=Zhang |first2=Qi |last3=Chen |first3=Baiyang |last4=Wang |first4=Lei |last5=Zhu |first5=Rongshu |last6=Yang |first6=Jie |date=2021 |title=Hydrogen peroxide formation in water during the VUV/UV irradiation process: Impacts and mechanisms of selected anions |url=https://linkinghub.elsevier.com/retrieve/pii/S0013935121000451 |journal=Environmental Research |language=en |volume=195 |pages=110751 |doi=10.1016/j.envres.2021.110751|pmid=33472042 }}</ref> Sea water contains 0.5 to 14&nbsp;μg/L of hydrogen peroxide, and freshwater contains 1 to 30&nbsp;μg/L.<ref name="offer"/> Concentrations in air are about 0.4 to 4&nbsp;μg/m<sup>3</sup>, varying over several [[orders of magnitude]] depending in conditions such as season, altitude, daylight and water vapor content. In rural nighttime air it is less than 0.014&nbsp;μg/m<sup>3</sup>, and in moderate [[Smog#Photochemical smog|photochemical smog]] it is 14 to 42&nbsp;μg/m<sup>3</sup>.<ref name="OEL 1996">[https://www.ecetoc.org/wp-content/uploads/2021/10/SR-10.pdf Special Report No. 10. Hydrogen Peroxide. OEL Criteria Document.] CAS No. 7722-84-1. July 1996.</ref>

The amount of hydrogen peroxide in biological systems can be assayed using a [[Enzyme assay|fluorometric assay]].<ref name="pmid8074285">{{cite journal |vauthors = Rapoport R, Hanukoglu I, Sklan D |title = A fluorimetric assay for hydrogen peroxide, suitable for NAD(P)H-dependent superoxide generating redox systems |journal = Analytical Biochemistry |volume = 218 |issue = 2 |pages = 309–313 |date = May 1994 |pmid = 8074285 |doi = 10.1006/abio.1994.1183 |url = https://zenodo.org/record/890715 |access-date = 1 July 2019 |url-status = live |s2cid = 40487242 |archive-url = https://web.archive.org/web/20200318091435/https://zenodo.org/record/890715 |archive-date = 18 March 2020}}</ref>

==Discovery==
[[Alexander von Humboldt]] is sometimes said to have been the first to report the first synthetic peroxide, [[barium peroxide]], in 1799 as a by-product of his attempts to decompose air, although this is disputed due to von Humboldt's ambiguous wording.<ref>{{cite journal |vauthors = Flohé L |title = Looking Back at the Early Stages of Redox Biology |journal = Antioxidants |volume = 9 |issue = 12 |pages = 1254 |date = December 2020 |pmid = 33317108 |pmc = 7763103 |doi = 10.3390/antiox9121254 |quote = I checked Humboldt’s pertinent publication carefully, but was unable to find an unambiguous proof of this assumption; the description of the starting materials (“Alaun-Erden” or “schwere Erden”) were just too unprecise to understand what kind of chemical experiments he performed. |doi-access = free}}</ref> Nineteen years later [[Louis Jacques Thénard]] recognized that this compound could be used for the preparation of a previously unknown compound, which he described as {{Lang|fr|eau oxygénée}} ("oxygenated water") — subsequently known as hydrogen peroxide.<ref>{{cite journal|title= Der tropfbar flüssige Sauerstoff, oder das oxygenierte Wasser|language= de| vauthors = Gilbert LW |url= https://books.google.com/books?id=xwYAAAAAMAAJ&pg=PA3 |journal= Annals of Physics |year= 1820|page= 3|volume= 65–66|issue= 1|doi= 10.1002/andp.18200640102 |bibcode= 1820AnP....64....1T}}</ref><ref>{{cite journal |vauthors = Thénard LJ |date = 1818 |title = Observations sur des nouvelles combinaisons entre l'oxigène et divers acides |journal = [[Annales de chimie et de physique]] |series = 2nd series |volume = 8 |pages = 306–312 |url = https://books.google.com/books?id=-N43AAAAMAAJ&pg=PA306 |access-date = 9 February 2016 |archive-url = https://web.archive.org/web/20160903130555/https://books.google.com/books?id=-N43AAAAMAAJ&pg=PA306 |archive-date = 3 September 2016 |url-status = live}}</ref><ref>{{cite journal |url=https://www.accessscience.com/content/hydrogen-peroxide/329200 |title=Hydrogen peroxide |vauthors = Giguère PA |author-link=Paul-Antoine Giguère |website=Access Science |publisher=McGraw-Hill Education |access-date=28 November 2018 |quote=Hydrogen peroxide was discovered in 1818 by the French chemist Louis-Jacques Thenard, who named it eau oxygénée (oxygenated water). |doi=10.1036/1097-8542.329200 |archive-url=https://web.archive.org/web/20181130071610/https://www.accessscience.com/content/hydrogen-peroxide/329200 |archive-date=30 November 2018 |url-status=live}}</ref>

An improved version of Thénard's process used [[hydrochloric acid]], followed by addition of [[sulfuric acid]] to precipitate the [[barium sulfate]] byproduct. This process was used from the end of the 19th century until the middle of the 20th century.<ref name = jonesclark>{{cite book| vauthors = Jones CW, Clark JH |title =Applications of Hydrogen Peroxide and Derivatives|publisher= Royal Society of Chemistry|date =1999|isbn = 978-0-85404-536-5}}</ref>

The bleaching effect of peroxides and their salts on [[natural dye]]s had been known since Thénard's experiments in the 1820s, but early attempts of industrial production of peroxides failed. The first plant producing hydrogen peroxide was built in 1873 in [[Berlin]]. The discovery of the synthesis of hydrogen peroxide by [[electrolysis]] with [[sulfuric acid]] introduced the more efficient electrochemical method. It was first commercialized in 1908 in [[Weißenstein]], [[Carinthia (state)|Carinthia]], Austria. The [[anthraquinone process]], which is still used, was developed during the 1930s by the German chemical manufacturer [[IG Farben]] in [[Ludwigshafen]]. The increased demand and improvements in the synthesis methods resulted in the rise of the annual production of hydrogen peroxide from 35,000 tonnes in 1950, to over 100,000 tonnes in 1960, to 300,000 tonnes by 1970; by 1998 it reached 2.7 million tonnes.<ref name="offer">{{cite journal |vauthors = Offermanns H, Dittrich G, Steiner N |author-link = Heribert Offermanns |year = 2000 |title = Wasserstoffperoxid in Umweltschutz und Synthese |journal = Chemie in unserer Zeit |volume = 34 |issue = 3 |page = 150 |doi = 10.1002/1521-3781(200006)34:3<150::AID-CIUZ150>3.0.CO;2-A}}</ref>

Early attempts failed to produce neat hydrogen peroxide. Anhydrous hydrogen peroxide was first obtained by [[vacuum distillation]].<ref>{{cite journal |vauthors = Wolffenstein R |date=October 1894 |title=Concentration und Destillation von Wasserstoffsuperoxyd |journal=Berichte der Deutschen Chemischen Gesellschaft |language=de |doi=10.1002/cber.189402703127 |volume=27 |issue=3 |pages=3307–12 |url=https://gallica.bnf.fr/ark:/12148/bpt6k90736r/f704.image.langEN |access-date=29 June 2014 |archive-url=https://web.archive.org/web/20160213231934/https://gallica.bnf.fr/ark:/12148/bpt6k90736r/f704.image.langEN |archive-date=13 February 2016 |url-status=live}}</ref>

Determination of the molecular structure of hydrogen peroxide proved to be very difficult. In 1892, the Italian physical chemist Giacomo Carrara (1864–1925) determined its molecular mass by [[freezing-point depression]], which confirmed that its molecular formula is {{chem2|H2O2}}.<ref>{{cite journal |vauthors = Carrara G |date = 1892 |url = https://books.google.com/books?id=Yk46AQAAMAAJ&pg=PA19 |title = Sul peso molecolare e sul potere rifrangente dell' acqua ossigenata |trans-title = On the molecular weight and on the refracting power of hydrogen peroxide |archive-url = https://web.archive.org/web/20160904175937/https://books.google.com/books?id=Yk46AQAAMAAJ&pg=PA19 |archive-date = 4 September 2016 |journal = Atti della Reale Accademia dei Lincei |volume = 1 |issue = 2| pages = 19–24}}<br/>
Carrara's findings were confirmed by: W. R. Orndorff and John White (1893) [https://books.google.com/books?id=QKYwAAAAYAAJ&pg=PA347 "The molecular weight of hydrogen peroxide and of benzoyl peroxide,"] {{Webarchive|url=https://web.archive.org/web/20160904221021/https://books.google.com/books?id=QKYwAAAAYAAJ&pg=PA347 |date=4 September 2016}} ''American Chemical Journal'', '''15''' : 347–356.</ref> {{chem2|H2O\dO}} seemed to be just as possible as the modern structure, and as late as in the middle of the 20th century at least half a dozen hypothetical isomeric variants of two main options seemed to be consistent with the available evidence.<ref>See, for example:
* In 1882, Kingzett proposed as a structure {{chem2|H2O\dO}}. See: {{cite journal |vauthors = Kingzett T |date = 29 September 1882 |title = On the activity of oxygen and the mode of formation of hydrogen dioxide |url = https://books.google.com/books?id=1OYEAAAAQAAJ&pg=RA1-PA141 |journal = The Chemical News |volume = 46 |issue = 1192 |pages = 141–2 |access-date = 9 February 2016 |archive-url = https://web.archive.org/web/20160903031312/https://books.google.com/books?id=1OYEAAAAQAAJ&pg=RA1-PA141 |archive-date = 3 September 2016 |url-status = live}}
* In his 1922 textbook, Joseph Mellor considered three hypothetical molecular structures for hydrogen peroxide, admitting (p. 952): "...&nbsp;the constitution of this compound has not been yet established by unequivocal experiments". See: Joseph William Mellor, ''A Comprehensive Treatise on Inorganic and Theoretical Chemistry'', vol. 1 (London, England: Longmans, Green and Co., 1922), [https://books.google.com/books?id=PnjVAAAAMAAJ&pg=PA952 p. 952–956.] {{Webarchive|url=https://web.archive.org/web/20160903145901/https://books.google.com/books?id=PnjVAAAAMAAJ&pg=PA952 |date=3 September 2016}}
* W. C. Schumb, C. N. Satterfield, and R. L. Wentworth (1 December 1953) [https://hydrogen-peroxide.us/chemical-properties/MIT-Schumb_etal-hydrogen_Peroxide_ch5_n_ch6-1954.pdf "Report no. 43: Hydrogen peroxide, Part two"] {{Webarchive|url=https://web.archive.org/web/20150226181901/https://hydrogen-peroxide.us/chemical-properties/MIT-Schumb_etal-hydrogen_Peroxide_ch5_n_ch6-1954.pdf |date=26 February 2015}}, Office of Naval Research, Contract No. N5ori-07819 On p. 178, the authors present six hypothetical models (including cis-trans isomers) for hydrogen peroxide's molecular structure. On p. 184, the present structure is considered almost certainly correct—although a small doubt remained. (Note: The report by Schumb et al. was reprinted as: W. C. Schumb, C. N. Satterfield, and R. L. Wentworth, ''Hydrogen Peroxide'' (New York, New York: Reinhold Publishing Corp. (American Chemical Society Monograph), 1955).)</ref> In 1934, the English mathematical physicist [[William Penney, Baron Penney|William Penney]] and the Scottish physicist [[Gordon Sutherland]] proposed a molecular structure for hydrogen peroxide that was very similar to the presently accepted one.<ref>{{cite journal |vauthors = Penney WG, Sutherland GB |year = 1934 |title = The theory of the structure of hydrogen peroxide and hydrazine |journal = Journal of Chemical Physics |volume = 2 |issue = 8| pages = 492–8 |doi=10.1063/1.1749518| bibcode = 1934JChPh...2..492P}}</ref><ref>{{cite journal |vauthors = Penney WG, Sutherland GB |year = 1934 |title = A note on the structure of H<sub>2</sub>O<sub>2</sub> and H<sub>4</sub>N<sub>2</sub> with particular reference to electric moments and free rotation |journal = Transactions of the Faraday Society |volume = 30 |pages = 898–902 |doi = 10.1039/tf934300898b}}</ref>

==Production==
[[File:Riedl-Pfleiderer process.svg|420px|right|thumb|[[Catalytic cycle]] for the [[anthraquinone process]] to produce hydrogen peroxide: an anthraquinone (right) is reduced using hydrogen to produce the corresponding anthrahydroquinone (left). This is oxidized using oxygen to produce hydrogen peroxide and recover anthraquinone.]]
In 1994, world production of {{chem2|H2O2}} was around 1.9 million tonnes and grew to 2.2 million in 2006,<ref name="HageLienke"/> most of which was at a concentration of 70% or less. In that year, bulk 30% {{chem2|H2O2}} sold for around 0.54 [[USD]]/[[Kilogram|kg]], equivalent to US$1.50/kg (US$0.68/[[pound (mass)|lb]]) on a "100% basis".<ref name="Antra"/>{{clarify|date=September 2020}}

Today, hydrogen peroxide is manufactured almost exclusively by the [[anthraquinone process]], which was originally developed by [[BASF]] in 1939. It begins with the reduction of an [[anthraquinone]] (such as [[2-Ethylanthraquinone|2-ethylanthraquinone]] or the 2-amyl derivative) to the corresponding anthrahydroquinone, typically by [[hydrogenation]] on a [[palladium]] [[catalysis|catalyst]]. In the presence of [[oxygen]], the anthrahydroquinone then undergoes [[autoxidation]]: the labile hydrogen atoms of the [[hydroxy group]]s transfer to the oxygen molecule, to give hydrogen peroxide and regenerating the anthraquinone. Most commercial processes achieve oxidation by bubbling [[compressed air]] through a solution of the anthrahydroquinone, with the hydrogen peroxide then [[Liquid–liquid extraction|extracted]] from the solution and the anthraquinone recycled back for successive cycles of hydrogenation and oxidation.<ref name="Antra">{{cite journal |vauthors = Campos-Martin JM, Blanco-Brieva G, Fierro JL |title = Hydrogen peroxide synthesis: an outlook beyond the anthraquinone process |journal = Angewandte Chemie |volume = 45 |issue = 42 |pages = 6962–84 |date = October 2006 |pmid = 17039551 |doi = 10.1002/anie.200503779 |s2cid = 23286196}}</ref><ref name="Riedl&Pleiderer">H. Riedl and G. Pfleiderer, U.S. Patent 2,158,525 (2 October 1936 in the US, and 10 October 1935 in Germany) to I. G. Farbenindustrie, Germany</ref>

The net reaction for the anthraquinone-catalyzed process is:<ref name="Antra"/>

:{{chem2|H2 + O2 → H2O2}}

The economics of the process depend heavily on effective recycling of the extraction solvents, the [[hydrogenation]] catalyst and the expensive [[quinone]].

[[File:Container JOTU501003 9.jpg|thumb|ISO tank container for hydrogen peroxide transportation]]
[[File:HydrogenPeroxideTankCarBoltonON.jpg|thumb|A tank car designed for transporting hydrogen peroxide by rail]]

===Historical methods===
Hydrogen peroxide was once prepared industrially by [[hydrolysis]] of [[ammonium persulfate]]:
:{{chem2|[NH4]2S2O8 + 2 H2O -> 2 [NH4]HSO4 + H2O2}}
{{chem2|[NH4]2S2O8}} was itself obtained by the [[electrolysis]] of a solution of [[ammonium bisulfate]] ({{chem2|[NH4]HSO4}}) in [[sulfuric acid]].<ref>{{Cite web|title=Preparing to manufacture hydrogen peroxide|url=https://www.idc-online.com/technical_references/pdfs/chemical_engineering/Preparing_to_Manufacture_Hydrogen_Peroxide.pdf|website=IDC Technologies|access-date=14 February 2022|archive-date=3 August 2021|archive-url=https://web.archive.org/web/20210803040838/http://www.idc-online.com/technical_references/pdfs/chemical_engineering/Preparing_to_Manufacture_Hydrogen_Peroxide.pdf|url-status=live}}</ref>

===Other routes===
Small amounts are formed by electrolysis, [[photochemistry]], [[electric arc]], and related methods.<ref Name="Mell1922">{{cite book |title=Modern Inorganic Chemistry| vauthors = Mellor JW |publisher=Longmans, Green and Co. |pages=192–5 |year=1922 |url=https://archive.org/details/b29807712}}</ref>

A commercially viable route for hydrogen peroxide via the reaction of hydrogen with oxygen favours production of water but can be stopped at the peroxide stage.<ref>{{citation | doi = 10.1002/9783527627547.ch8| chapter = Direct Synthesis of Hydrogen Peroxide: Recent Advances| title = Modern Heterogeneous Oxidation Catalysis| date = 2009| last1 = Centi| first1 = Gabriele| last2 = Perathoner| first2 = Siglinda| last3 = Abate| first3 = Salvatore| pages = 253–287| isbn = 978-3-527-31859-9}}</ref><ref name="Hutchings">{{cite journal |vauthors = Edwards JK, Solsona B, N EN, Carley AF, Herzing AA, Kiely CJ, Hutchings GJ |title = Switching off hydrogen peroxide hydrogenation in the direct synthesis process |journal = Science |volume = 323 |issue = 5917 |pages = 1037–41 |date = February 2009 |pmid = 19229032 |doi = 10.1126/science.1168980 |s2cid = 1828874 |bibcode = 2009Sci...323.1037E }}</ref> One economic obstacle has been that direct processes give a dilute solution uneconomic for transportation. None of these has yet reached a point where it can be used for industrial-scale synthesis.

==Reactions==
===Acid-base===
Hydrogen peroxide is about 1000 times stronger as an acid than water.<ref>{{Greenwood&Earnshaw2nd|page=633-637}}</ref>
:{{chem2|H2O2 <-> H+ + HO2-}} (p''K'' = 11.65)

===Disproportionation===
Hydrogen peroxide disproportionates to form water and oxygen with a [[Standard enthalpy change of reaction|Δ''H''<sup><s>o</s></sup>]] of –2884.5&nbsp;[[Kilojoule|kJ]]/[[Kilogram|kg]]<ref>{{Cite web|url=https://www.proakademia.eu/gfx/baza_wiedzy/461/nr_26_45-52_2_3.pdf|title=Decomposition of Hydrogen Peroxide — Kinetics and Review of Chosen Catalysts|access-date=30 August 2019|archive-url=https://web.archive.org/web/20181222153038/https://www.proakademia.eu/gfx/baza_wiedzy/461/nr_26_45-52_2_3.pdf|archive-date=22 December 2018|url-status=live}}</ref> and a Δ[[Entropy|S]] of 70.5&nbsp;J/(mol·K):

:{{chem2| 2 H2O2 -> 2 H2O + O2 }}

The rate of decomposition increases with rise in temperature, concentration, and [[pH]]. {{chem2|H2O2}} is unstable under alkaline conditions. Decomposition is catalysed by various redox-active ions or compounds, including most [[transition metal]]s and their compounds (e.g. [[manganese dioxide]] ({{chem2|MnO2}}), [[silver]], and [[platinum]]).<ref>{{cite book |vauthors = Petrucci RH |date=2007 |title=General Chemistry: Principles & Modern Applications |edition=9th |publisher=Prentice Hall |isbn=978-0-13-149330-8 |page=[https://archive.org/details/generalchemistry0000petr/page/606 606] |url=https://archive.org/details/generalchemistry0000petr/page/606}}</ref>

===Oxidation reactions===
The [[redox]] properties of hydrogen peroxide depend on pH. In acidic solutions, {{chem2|H2O2}} is a powerful [[oxidizer]].
{| class="wikitable"
|-style="vertical-align: top;"
![[Oxidant|Oxidizing<br>reagent]] !!Reduced<br>product
! [[Oxidation potential|Oxidation<br>potential]]<br>(V)
|-
| [[fluorine|{{chem2|F2}}]]||[[Hydrogen fluoride|HF]]
| align="center"|3.0
|-
| [[ozone|{{chem2|O3}}]]||[[Oxygen|{{chem2|O2}}]]
| align="center"|2.1
|-
| {{chem2|H2O2}}||[[Water|{{chem2|H2O}}]]
| align="center"|1.8
|-
| [[potassium permanganate|{{chem2|KMnO4}}]]||[[manganese dioxide|{{chem2|MnO2}}]]
| align="center"|1.7
|-
| [[chlorine dioxide|{{chem2|ClO2}}]]||[[Hypochlorous acid|HClO]]
| align="center"|1.5
|-
| [[chlorine|{{chem2|Cl2}}]]||[[Chloride|{{chem2|Cl−}}]]
| align="center"|1.4
|}

[[Sulfite]] ({{chem2|SO3(2−)}}) is oxidized to [[sulfate]] ({{chem2|SO4(2−)}}).

===Reduction reactions===
Under [[alkaline]] conditions, hydrogen peroxide is a reductant. When {{chem2|H2O2}} acts as a reducing agent, [[oxygen]] gas is also produced. For example, hydrogen peroxide will reduce [[sodium hypochlorite]] and [[potassium permanganate]], which is a convenient method for preparing [[oxygen]] in the laboratory:
:{{chem2|NaOCl + H2O2 -> O2 + NaCl + H2O}}
:{{chem2|2 KMnO4 + 3 H2O2 -> 2 MnO2 + 2 KOH + 2 H2O + 3 O2}}

The oxygen produced from hydrogen peroxide and sodium [[hypochlorite]] is in [[singlet oxygen|the singlet state]].

Hydrogen peroxide also reduces [[silver oxide]] to [[silver]]:
:{{chem2|Ag2O + H2O2 -> 2 Ag + H2O + O2}}
Although usually a reductant, alkaline hydrogen peroxide converts Mn(II) to the dioxide:
:{{chem2|H2O2 + Mn(2+) + 2 OH- -> MnO2 + 2 H2O}}

In a related reaction, [[potassium permanganate]] is reduced to {{chem2|Mn(2+)}} by ''acidic'' {{chem2|H2O2}}:<ref name=House/>
:{{chem2|2 MnO4- + 5 H2O2 + 6 H+ -> 2 Mn^{2+} + 8 H2O + 5 O2}}

===Organic reactions===
Hydrogen peroxide is frequently used as an [[Redox|oxidizing agent]]. Illustrative is oxidation of [[thioether]]s to form [[sulfoxide]]s, such as conversion of [[thioanisole]] to [[methyl phenyl sulfoxide]]:<ref>{{cite journal |vauthors = Ravikumar KS, Kesavan V, Crousse B, Bonnet-Delpon D, Bégué JP |year = 2003 |title = Mild and Selective Oxidation of Sulfur Compounds in Trifluoroethanol: Diphenyldisulfide and Methyl phenyl Sulfoxide |journal = Org. Synth. |volume = 80 |page = 184 |doi = 10.15227/orgsyn.080.0184}}</ref><ref>{{Cite journal |vauthors = Xu WL, Li YZ, Zhang QS, Zhu HS |title = A Selective, Convenient, and Efficient Conversion of Sulfides to Sulfoxides |doi = 10.1055/s-2004-44387 |journal = Synthesis |issue = 2 |pages = 227–232 |year = 2004}}</ref>
:{{chem2| Ph\-S\-CH3 + H2O2 -> Ph\-S(O)\-CH3 + H2O }}

Alkaline hydrogen peroxide is used for [[epoxidation]] of electron-deficient alkenes such as [[acrylic acid]] derivatives,<ref>{{cite journal |vauthors = Mayer RJ, Ofial AR |title = Nucleophilic Reactivities of Bleach Reagents |journal = Organic Letters |volume = 20 |issue = 10 |pages = 2816–20 |date = May 2018 |pmid = 29741385 |doi = 10.1021/acs.orglett.8b00645}}</ref> and for the oxidation of [[alkylborane]]s to [[ethanol|alcohol]]s, the second step of [[hydroboration-oxidation]]. It is also the principal reagent in the [[Dakin oxidation]] process.

===Precursor to other peroxide compounds===
Hydrogen peroxide is a weak acid, forming [[hydroperoxide]] or [[peroxide]] [[Salt (chemistry)|salts]] with many metals.

It also converts metal oxides into the corresponding peroxides. For example, upon treatment with hydrogen peroxide, [[chromic acid]] ({{chem2|CrO3}} and {{chem2|H2SO4}}) forms a blue peroxide [[Chromium(VI) oxide peroxide|{{chem2|CrO(O2)2}}]].

==Biochemistry==
[[File:Ascaridol.svg|thumb|upright=0.5|[[Ascaridole]]]]

===Production===
The aerobic oxidation of [[glucose]] in the presence of the enzyme [[glucose oxidase]] produces hydrogen peroxide. The conversion affords [[gluconolactone]]:<ref>{{cite journal |doi=10.1007/s00253-008-1407-4 |title=Glucose oxidase: Natural Occurrence, Function, Properties and Industrial Applications |date=2008 |last1=Wong |first1=Chun Ming |last2=Wong |first2=Kwun Hei |last3=Chen |first3=Xiao Dong |journal=Applied Microbiology and Biotechnology |volume=78 |issue=6 |pages=927–938 |pmid=18330562 |s2cid=2246466}}</ref>
:{{chem2|C6H12O6 + O2 -> C6H10O6 + H2O2}}

[[Superoxide dismutase]]s (SOD)s are [[enzyme]]s that promote the [[disproportionation]] of [[superoxide]] into [[oxygen]] and hydrogen peroxide.<ref>Löffler G. and Petrides, P. E. ''Physiologische Chemie''. 4 ed., pp. 321–322, Springer, Berlin 1988, {{ISBN|3-540-18163-6}} (in German)</ref>

:{{chem2| 2 O2- + 2 H+ -> O2 + H2O2 }}
:{{chem2| 2 H2O2 -> O2 + 2 H2O }}

[[Peroxisome]]s are [[organelle]]s found in virtually all [[eukaryotic]] cells.<ref name="pmid20124343">{{cite journal |vauthors = Gabaldón T |title = Peroxisome diversity and evolution |journal = Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences |volume = 365 |issue = 1541 |pages = 765–773 |date = March 2010 |pmid = 20124343 |pmc = 2817229 |doi = 10.1098/rstb.2009.0240}}</ref> They are involved in the [[catabolism]] of [[very long chain fatty acid]]s, [[Branched-chain-fatty-acid kinase|branched chain fatty acids]], [[D-amino acid|<small>D</small>-amino acids]], [[polyamine]]s, and biosynthesis of [[plasmalogens]] and [[ether phospholipid]]s, which are found in mammalian brains and lungs.<ref name="pmid16756494">{{cite journal |vauthors = Wanders RJ, Waterham HR |title = Biochemistry of mammalian peroxisomes revisited |journal = Annual Review of Biochemistry |volume = 75 |issue = 1 |pages = 295–332 |year = 2006 |pmid = 16756494 |doi = 10.1146/annurev.biochem.74.082803.133329}}</ref> They produce hydrogen peroxide in a process catalyzed by [[flavin adenine dinucleotide]] (FAD):<ref>{{cite book |vauthors = Nelson D, Cox C, Lehninger AL, Cox MM |url = https://books.google.com/books?id=wuLQCAOtC4MC&pg=PA663 |title = Lehninger Biochemie |archive-url = https://web.archive.org/web/20170228175147/https://books.google.com/books?id=wuLQCAOtC4MC&pg=PA663 |archive-date = 28 February 2017 |pages = 663–4 |publisher = Springer |date = 2001 |isbn = 3-540-41813-X |language = German}}</ref>

:{{chem2| R\-CH2\-CH2\-CO\-SCoA + O2 }}<chem>->[\ce{FAD}]</chem> {{chem2| R\-CH\dCH\-CO\-SCoA + H2O2 }}

Hydrogen peroxide arises by the degradation of [[adenosine monophosphate]], which yields [[hypoxanthine]]. Hypoxanthine is then oxidatively [[catabolism|catabolized]] first to [[xanthine]] and then to [[uric acid]], and the reaction is catalyzed by the enzyme [[xanthine oxidase]]:<ref name="lehninger932">Nelson, David; Cox, Michael; Lehninger, Albert L. and Cox, Michael M. [https://books.google.com/books?id=wuLQCAOtC4MC&pg=PA932 Lehninger Biochemie], p. 932, Springer, 2001, {{ISBN|3-540-41813-X}} (in German)</ref>

{{Image frame
|align=center
| content={{Biochem reaction subunit
|compound=Hypoxanthine
|image=Hypoxanthin.svg}}
{{Biochem reaction subunit
|enzyme=Xanthine oxidase
|for_subst={{H2O-nl}}, {{chem2|O2}}
|for_prod={{chem2|H2O2}}}}
{{Biochem reaction subunit
|compound=Xanthine
|image=Xanthin.svg}}
{{Biochem reaction subunit
|enzyme=Xanthine oxidase
|for_subst={{H2O-nl}}, {{chem2|O2}}
|for_prod={{chem2|H2O2}}}}
{{Biochem reaction subunit
|compound=Uric acid
|image=Harnsäure Ketoform.svg
|imagesize=120px}}
| caption=Degradation of hypoxanthine through xanthine to uric acid to form hydrogen peroxide.
|width=600}}

The degradation of [[guanosine monophosphate]] yields xanthine as an intermediate product which is then converted in the same way to uric acid with the formation of hydrogen peroxide.<ref name="lehninger932" />

===Consumption===
[[Catalase]], another peroxisomal enzyme, uses this {{chem2|H2O2}} to oxidize other substrates, including [[phenols]], [[formic acid]], [[formaldehyde]], and [[ethanol|alcohol]], by means of a peroxidation reaction:
:{{chem2| H2O2 + R'H2 -> R' + 2 H2O }}
thus eliminating the poisonous hydrogen peroxide in the process.

This reaction is important in liver and kidney cells, where the peroxisomes neutralize various toxic substances that enter the blood. Some of the [[ethanol]] humans drink is oxidized to [[acetaldehyde]] in this way.<ref>Riley, Edward P. ''et al''. (ed.) [https://books.google.com/books?id=TiSL4txuYN0C&pg=PA112 Fetal Alcoholspectrum Disorder Fasd: Management and Policy Perspectives] {{Webarchive|url=https://web.archive.org/web/20170228175446/https://books.google.com/books?id=TiSL4txuYN0C&pg=PA112 |date=28 February 2017}}, Wiley-VCH, 2010, {{ISBN|3-527-32839-4}} p. 112</ref> In addition, when excess {{chem2|H2O2}} accumulates in the cell, catalase converts it to {{chem2|H2O}} through this reaction:
: {{chem2|H2O2 -> 0.5 O2 + H2O}}
[[Glutathione peroxidase]], a [[selenoenzyme]], also catalyzes the disproportionation of hydrogen peroxide.

===Fenton reaction===
The reaction of [[Ferrous|{{chem2|Fe(2+)}}]] and hydrogen peroxide is the basis of the [[Fenton reaction]], which generates [[hydroxyl radical]]s, which are of significance in biology:
:{{chem2|Fe(II) + H2O2 -> Fe(III)OH + HO*}}

The Fenton reaction explains the toxicity of hydrogen peroxides because the hydroxyl radicals rapidly and irreversibly oxidize all organic compounds, including [[protein]]s, [[membrane lipid]]s, and [[DNA]].<ref>Löffler G. and Petrides, P. E. ''Physiologische Chemie''. 4 ed., p. 288, Springer, Berlin 1988, {{ISBN|3-540-18163-6}} (in German)</ref> Hydrogen peroxide is a significant source of [[DNA damage (naturally occurring)|oxidative DNA damage]] in living cells. DNA damage includes formation of [[8-Oxo-2'-deoxyguanosine]] among many other altered bases, as well as strand breaks, inter-strand crosslinks, and deoxyribose damage.<ref name="Halliwell2021" /> By interacting with Cl¯, hydrogen peroxide also leads to chlorinated DNA bases.<ref name="Halliwell2021">{{cite journal |vauthors=Halliwell B, Adhikary A, Dingfelder M, Dizdaroglu M |title=Hydroxyl radical is a significant player in oxidative DNA damage in vivo |journal=Chem Soc Rev |volume=50 |issue=15 |pages=8355–60 |date=August 2021 |pmid=34128512 |pmc=8328964 |doi=10.1039/d1cs00044f }}</ref> Hydroxyl radicals readily damage vital cellular components, especially those of the [[mitochondria]].<ref>{{cite journal |vauthors = Giorgio M, Trinei M, Migliaccio E, Pelicci PG |title = Hydrogen peroxide: a metabolic by-product or a common mediator of ageing signals? |journal = Nature Reviews. Molecular Cell Biology |volume = 8 |issue = 9 |pages = 722–8 |date = September 2007 |pmid = 17700625 |doi = 10.1038/nrm2240 |s2cid = 6407526 }}</ref><ref>{{cite journal |vauthors = Gonzalez D, Bejarano I, Barriga C, Rodriguez AB, Pariente JA |year = 2010 |title = Oxidative Stress-Induced Caspases are Regulated in Human Myeloid HL-60 Cells by Calcium Signal |journal = Current Signal Transduction Therapy |volume = 5 |issue = 2| pages = 181–6 |doi = 10.2174/157436210791112172}}</ref><ref>{{cite journal |vauthors = Bejarano I, Espino J, González-Flores D, Casado JG, Redondo PC, Rosado JA, Barriga C, Pariente JA, Rodríguez AB |display-authors = 6 |title = Role of Calcium Signals on Hydrogen Peroxide-Induced Apoptosis in Human Myeloid HL-60 Cells |journal = International Journal of Biomedical Science |volume = 5 |issue = 3 |pages = 246–256 |date = September 2009 |doi = 10.59566/IJBS.2009.5246 |pmid = 23675144 |pmc = 3614781}}</ref> The compound is a major factor implicated in the [[free-radical theory of aging]], based on its ready conversion into a [[hydroxyl radical]].

===Function===
[[File:Pheropsophus verticalis 01 Pengo.jpg|thumb|130px|Australian [[bombardier beetle]]]]Eggs of [[sea urchin]], shortly after fertilization by a sperm, produce hydrogen peroxide. It is then converted to [[hydroxyl radical]]s (HO•), which initiate [[radical polymerization]], which surrounds the eggs with a protective layer of [[polymer]].

The [[bombardier beetle]] combines [[hydroquinone]] and hydrogen peroxide, leading to a violent [[exothermic]] [[chemical reaction]] to produce boiling, foul-smelling liquid that partially becomes a [[gas]] ([[flash evaporation]]) and is expelled through an outlet valve with a loud popping sound.<ref>{{cite journal| vauthors = Schildknecht H, Holoubek K |title=The bombardier beetle and its chemical explosion|journal=Angewandte Chemie|volume=73|pages=1–7|year=1961|doi=10.1002/ange.19610730102}}</ref><ref name="ncse">{{cite journal |vauthors = Weber CG |title=The Bombardier Beetle Myth Exploded |journal=Creation/Evolution |volume=2 |issue=1 |pages=1–5 |date=Winter 1981 |url=https://ncse.com/cej/2/1/bombardier-beetle-myth-exploded |access-date=12 November 2017 |archive-url=https://web.archive.org/web/20170929125624/https://ncse.com/cej/2/1/bombardier-beetle-myth-exploded |archive-date=29 September 2017 |url-status=live}}</ref><ref name="to">{{cite web |vauthors = Isaak M |date=30 May 2003 |title=Bombardier Beetles and the Argument of Design |website=[[TalkOrigins Archive]] |url=https://www.talkorigins.org/faqs/bombardier.html |access-date=12 November 2017 |archive-url=https://web.archive.org/web/20171116235917/https://www.talkorigins.org/faqs/bombardier.html |archive-date=16 November 2017 |url-status=live}}</ref>

As a proposed [[signaling molecule]], hydrogen peroxide may regulate a wide variety of biological processes.<ref>{{cite journal |vauthors = Veal EA, Day AM, Morgan BA |title = Hydrogen peroxide sensing and signaling |journal = Molecular Cell |volume = 26 |issue = 1 |pages = 1–14 |date = April 2007 |pmid = 17434122 |doi = 10.1016/j.molcel.2007.03.016 |doi-access = free}}</ref><ref>{{Cite web|title=Wie Pflanzen sich schützen, Helmholtz-Institute of Biochemical Plant Pathology (in German)|url=https://www.helmholtz-muenchen.de/biop/printversionen/pdf/aktuelles/pflanzenschuetzen_no.pdf|url-status=dead|archive-url=https://web.archive.org/web/20110723120528/https://www.helmholtz-muenchen.de/biop/printversionen/pdf/aktuelles/pflanzenschuetzen_no.pdf|archive-date=23 July 2011|access-date=14 February 2022|publisher=Helmholtz-Institute of Biochemical Plant Pathology|language=de}}</ref> At least one study has tried to link hydrogen peroxide production to cancer.<ref>{{cite journal |vauthors = López-Lázaro M |title = Dual role of hydrogen peroxide in cancer: possible relevance to cancer chemoprevention and therapy |journal = Cancer Letters |volume = 252 |issue = 1 |pages = 1–8 |date = July 2007 |pmid = 17150302 |doi = 10.1016/j.canlet.2006.10.029}}</ref>

==Uses==
===Bleaching===
About 60% of the world's production of hydrogen peroxide is used for [[bleaching of wood pulp|pulp- and paper-bleaching]].<ref name="HageLienke">{{cite journal |vauthors = Hage R, Lienke A |title = Applications of transition-metal catalysts to textile and wood-pulp bleaching |journal = Angewandte Chemie |volume = 45 |issue = 2 |pages = 206–222 |date = December 2005 |pmid = 16342123 |doi = 10.1002/anie.200500525 |url = https://onlinelibrary.wiley.com/doi/10.1002/anie.200500525 |access-date = 14 February 2022 |url-status = live |archive-url = https://web.archive.org/web/20220125060924/https://onlinelibrary.wiley.com/doi/10.1002/anie.200500525 |archive-date = 25 January 2022}}</ref> The second major industrial application is the manufacture of [[sodium percarbonate]] and [[sodium perborate]], which are used as mild bleaches in [[laundry]] [[detergent]]s. A representative conversion is:
:{{chem2|Na2B4O7 + 4 H2O2 + 2 NaOH -> 2 Na2B2O4(OH)4 + H2O}}
Sodium percarbonate, which is an adduct of [[sodium carbonate]] and hydrogen peroxide, is the active ingredient in such laundry products as [[OxiClean]] and [[Tide (detergent)|Tide laundry detergent]]. When dissolved in water, it releases hydrogen peroxide and sodium carbonate.<ref name= jonesclark/> By themselves these bleaching agents are only effective at wash temperatures of {{convert|60|C}} or above and so, often are used in conjunction with [[bleach activator]]s, which facilitate cleaning at lower temperatures.

Hydrogen peroxide has also been used as a [[flour bleaching agent]] and a [[tooth whitening|tooth and bone whitening]] agent.

===Production of organic peroxy compounds===
It is used in the production of various [[organic peroxide]]s with [[dibenzoyl peroxide]] being a high volume example.<ref name=Ullmann>{{Ullmann|first1=Herbert|last1=Klenk|first2=Peter H.|last2=Götz|first3=Rainer|last3=Siegmeier|first4=Wilfried|last4=Mayr|title=Peroxy Compounds, Organic|doi=10.1002/14356007.a19_199.pub2}}</ref> [[Peroxy acid]]s, such as [[peracetic acid]] and [[Meta-Chloroperoxybenzoic acid|''meta''-chloroperoxybenzoic acid]] also are produced using hydrogen peroxide. Hydrogen peroxide has been used for creating [[organic peroxide]]-based explosives, such as [[acetone peroxide]]. It is used as an initiator in [[Radical polymerization|polymerizations]]. Hydrogen peroxide reacts with certain di-[[ester]]s, such as [[phenyl oxalate ester]] (cyalume), to produce [[chemiluminescence]]; this application is most commonly encountered in the form of [[glow stick]]s.

===Production of inorganic peroxides===
The reaction with [[borax]] leads to [[sodium perborate]], a bleach used in laundry detergents:
:{{chem2| Na2B4O7 + 4 H2O2 + 2 NaOH -> 2 Na2B2O4(OH)4 + H2O }}

===Sewage treatment===
Hydrogen peroxide is used in certain waste-water treatment processes to remove organic impurities. In [[advanced oxidation process]]ing, the [[Fenton reaction]]<ref>{{cite book| veditors = Tarr MA |title=Chemical degradation methods for wastes and pollutants environmental and industrial applications|date=2003|publisher=M. Dekker|location=New York|isbn=978-0-203-91255-3|page=165}}</ref><ref>{{cite journal| vauthors = Pignatello JJ, Oliveros E, MacKay A |title=Advanced Oxidation Processes for Organic Contaminant Destruction Based on the Fenton Reaction and Related Chemistry|journal=Critical Reviews in Environmental Science and Technology|date=January 2006|volume=36|issue=1|pages=1–84|doi=10.1080/10643380500326564|bibcode=2006CREST..36....1P |s2cid=93052585}}</ref> gives the highly reactive [[hydroxyl radical]] (•OH). This degrades organic compounds, including those that are ordinarily robust, such as [[Aromatic hydrocarbon|aromatic]] or [[halogenated compound]]s.<ref>{{cite journal| vauthors = Pera-Titus M, Garcıa-Molina V, Baños MA, Giménez J, Esplugas S |title=Degradation of chlorophenols by means of advanced oxidation processes: a general review|journal=Applied Catalysis B: Environmental|date=February 2004|volume=47|issue=4|pages=219–256|doi=10.1016/j.apcatb.2003.09.010}}</ref> It can also oxidize [[sulfur]]-based compounds present in the waste; which is beneficial as it generally reduces their odour.<ref>{{cite encyclopedia |vauthors = Goor G, Glenneberg J, Jacobi S |encyclopedia = Ullmann's Encyclopedia of Industrial Chemistry |year = 2007 |publisher = Wiley-VCH |location = Weinheim |doi = 10.1002/14356007.a13_443.pub2 |chapter = Hydrogen Peroxide |isbn = 978-3-527-30673-2}}</ref>

===Disinfectant===
Hydrogen peroxide may be used for the sterilization of various surfaces,<ref name="ascenzi">{{cite book| veditors = Ascenzi JM |title=Handbook of disinfectants and antiseptics|date=1996|publisher=M. Dekker|location=New York|isbn=978-0-8247-9524-5|page=161}}</ref> including surgical instruments,<ref>{{cite journal |vauthors = Rutala WA, Weber DJ |title = Disinfection and sterilization in health care facilities: what clinicians need to know |journal = Clinical Infectious Diseases |volume = 39 |issue = 5 |pages = 702–9 |date = September 2004 |pmid = 15356786 |doi = 10.1086/423182 |doi-access = free}}</ref> and may be deployed as a vapour ([[Vaporized hydrogen peroxide|VHP]]) for room sterilization.<ref>{{cite journal |vauthors = Falagas ME, Thomaidis PC, Kotsantis IK, Sgouros K, Samonis G, Karageorgopoulos DE |title = Airborne hydrogen peroxide for disinfection of the hospital environment and infection control: a systematic review |journal = The Journal of Hospital Infection |volume = 78 |issue = 3 |pages = 171–7 |date = July 2011 |pmid = 21392848 |doi = 10.1016/j.jhin.2010.12.006}}</ref> {{chem2|H2O2}} demonstrates broad-spectrum efficacy against viruses, bacteria, yeasts, and bacterial spores.<ref>{{cite book| veditors = Block SS |title=Disinfection, sterilization, and preservation|date=2000|publisher=Lea & Febiger|location=Philadelphia|isbn=978-0-683-30740-5|pages=185–204|edition=5th|chapter=Chapter 9: Peroxygen compounds}}</ref><ref name="cdc_sporicidal">{{cite web |title=Chemical Disinfectants — Disinfection & Sterilization Guidelines — Guidelines Library — Infection Control — CDC |url=https://www.cdc.gov/infectioncontrol/guidelines/disinfection/disinfection-methods/chemical.html#Hydrogen |website=www.cdc.gov |access-date=12 April 2020 |language=en-us |date=4 April 2019 |archive-date=1 July 2017 |archive-url=https://web.archive.org/web/20170701211440/https://www.cdc.gov/infectioncontrol/guidelines/disinfection/disinfection-methods/chemical.html#Hydrogen |url-status=live}}</ref> In general, greater activity is seen against [[Gram-positive]] than [[Gram-negative]] bacteria; however, the presence of [[catalase]] or other [[peroxidase]]s in these organisms may increase tolerance in the presence of lower concentrations.<ref>{{cite journal |vauthors = McDonnell G, Russell AD |title = Antiseptics and disinfectants: activity, action, and resistance |journal = Clinical Microbiology Reviews |volume = 12 |issue = 1 |pages = 147–179 |date = January 1999 |pmid = 9880479 |pmc = 88911 |doi = 10.1128/cmr.12.1.147}}</ref> Lower levels of concentration (3%) will work against most spores; higher concentrations (7 to 30%) and longer contact times will improve sporicidal activity.<ref name="cdc_sporicidal"/><ref>{{cite book| veditors = Block SS |title= Disinfection, sterilization, and preservation|date=2000|publisher=Lea & Febiger|location=Philadelphia|isbn=978-0-683-30740-5|pages=529–543|edition=5th|chapter=Chapter 27: Chemical Sporicidal and Sporostatic Agents}}</ref>

Hydrogen peroxide is seen as an environmentally safe alternative to [[chlorine]]-based bleaches, as it degrades to form oxygen and water and it is [[generally recognized as safe]] as an [[antimicrobial agent]] by the U.S. [[Food and Drug Administration]] (FDA).<ref>{{cite web|title=Sec. 184.1366 Hydrogen peroxide |publisher=U.S. Government Printing Office via GPO Access |url=https://a257.g.akamaitech.net/7/257/2422/04nov20031500/edocket.access.gpo.gov/cfr_2001/aprqtr/21cfr184.1366.htm |date=1 April 2001 |access-date=7 July 2007 |url-status=dead |archive-url=https://web.archive.org/web/20070703092508/https://a257.g.akamaitech.net/7/257/2422/04nov20031500/edocket.access.gpo.gov/cfr_2001/aprqtr/21cfr184.1366.htm |archive-date=3 July 2007}}</ref>

===Propellant===
{{further|High-test peroxide}}
[[File:Rocket Belt Propulsion.svg|thumb|upright|[[Bell Rocket Belt|Rocket-belt]] hydrogen peroxide propulsion system used in a [[jet pack]]]]
High-concentration {{chem2|H2O2}} is referred to as "high-test peroxide" (HTP). It can be used as either a [[monopropellant]] (not mixed with fuel) or the oxidizer component of a [[bipropellant rocket]]. Use as a monopropellant takes advantage of the decomposition of 70–98% concentration hydrogen peroxide into steam and oxygen. The propellant is pumped into a reaction chamber, where a catalyst, usually a silver or platinum screen, triggers decomposition, producing steam at over {{convert|600|C|sigfig=2}}, which is expelled through a [[nozzle]], generating [[thrust]]. {{chem2|H2O2}} monopropellant produces a maximal [[specific impulse]] (''I''<sub>sp</sub>) of 161 s (1.6 [[newton-second|kN·s]]/kg). Peroxide was the first major monopropellant adopted for use in rocket applications. [[Hydrazine]] eventually replaced hydrogen peroxide monopropellant thruster applications primarily because of a 25% increase in the vacuum specific impulse.<ref>{{Cite conference |conference=42nd AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit |location=Sacramento, California |url=https://www.hydrogen-peroxide.us/history-US-General-Kinetics/AIAA-2006-5236_hydrogen_peroxide_versus_hydrazine.pdf |title=System Trade Parameter Comparison of Monopropellants: Hydrogen Peroxide vs Hydrazine and Others |archive-url=https://web.archive.org/web/20141210233955/https://www.hydrogen-peroxide.us/history-US-General-Kinetics/AIAA-2006-5236_hydrogen_peroxide_versus_hydrazine.pdf |archive-date=10 December 2014 |url-status=dead |date=9–12 July 2006 |vauthors = Wernimont EJ}}</ref> Hydrazine (toxic) and hydrogen peroxide (less toxic [ACGIH TLV 0.01 and 1 ppm respectively]) are the only two monopropellants (other than cold gases) to have been widely adopted and utilized for propulsion and power applications.{{citation needed|date=October 2018}} The [[Bell Rocket Belt]], [[reaction control system]]s for [[Bell X-1|X-1]], [[X-15]], [[Centaur (rocket stage)|Centaur]], [[Project Mercury|Mercury]], [[Little Joe (rocket)|Little Joe]], as well as the turbo-pump gas generators for X-1, X-15, Jupiter, Redstone and Viking used hydrogen peroxide as a monopropellant.<ref>{{Cite web |url=https://www.hydrogen-peroxide.us/uses-monoprop-steam-generation/AIAA-1999-2880_The_Use_of_Hydrogen_Peroxide_for_Propulsion_and_Power-pitch.pdf |title=The Use of Hydrogen Peroxide for Propulsion and Power |vauthors = Ventura M, Mullens P |publisher=General Kinetics, LLC |date=19 June 1999 |access-date=10 December 2014 |archive-url=https://web.archive.org/web/20141210233830/https://www.hydrogen-peroxide.us/uses-monoprop-steam-generation/AIAA-1999-2880_The_Use_of_Hydrogen_Peroxide_for_Propulsion_and_Power-pitch.pdf |archive-date=10 December 2014 |url-status=dead}}</ref> The [[RD-107]] engines (used from 1957 to present) in the [[R-7 (rocket family)|R-7]] series of rockets decompose hydrogen peroxide to power the turbopumps.

In bipropellant applications, {{chem2|H2O2}} is decomposed to oxidize a burning fuel. Specific impulses as high as 350 s (3.5&nbsp;kN·s/kg) can be achieved, depending on the fuel. Peroxide used as an oxidizer gives a somewhat lower ''I''<sub>sp</sub> than liquid oxygen but is dense, storable, and non-cryogenic and can be more easily used to drive gas turbines to give high pressures using an efficient ''closed cycle''. It may also be used for regenerative cooling of rocket engines. Peroxide was used very successfully as an oxidizer in World War II German rocket motors (e.g., [[T-Stoff]], containing oxyquinoline stabilizer, for both the [[Walter HWK 109-500]] ''Starthilfe'' [[RATO]] externally podded monopropellant booster system and the [[Walter HWK 109-509]] rocket motor series used for the [[Me 163]]B), most often used with [[C-Stoff]] in a self-igniting [[hypergolic]] combination, and for the low-cost British [[Black Knight (rocket)|Black Knight]] and [[Black Arrow]] launchers. Presently, HTP is used on ILR-33 AMBER<ref>{{Cite web| vauthors = Cieśliński D |date=2021|title=Polish civil rockets' development overview|url=https://www.researchgate.net/publication/355481109|access-date=15 February 2022|archive-date=6 February 2022|archive-url= https://web.archive.org/web/20220206155954/https://www.researchgate.net/publication/355481109_Polish_civil_rockets%27_development_overview|url-status=live}}</ref> and Nucleus<ref>{{Cite web|title=Nucleus: A Very Different Way to Launch into Space|url=https://www.nammo.com/story/a-very-different-way-to-launch-into-space/|access-date=2022-02-06|website=Nammo|language=en-US|archive-date=6 February 2022|archive-url=https://web.archive.org/web/20220206155449/https://www.nammo.com/story/a-very-different-way-to-launch-into-space/|url-status=live}}</ref> suborbital rockets.<!--{{cite web| url = https://www.cue-dih.co.uk/aerospace/aeropdfs/htp_for_prop.pdf| title = Hydrogen Peroxide for Power and Propulsion}}-->

In the 1940s and 1950s, the [[Hellmuth Walter Kommanditgesellschaft|Hellmuth Walter KG]]–conceived [[gas turbine|turbine]] used hydrogen peroxide for use in [[submarine]]s while submerged; it was found to be too noisy and require too much maintenance compared to [[Submarine#Propulsion|diesel-electric]] power systems. Some [[torpedo]]es used hydrogen peroxide as oxidizer or propellant. Operator error in the use of hydrogen peroxide torpedoes was named as possible causes for the sinking of [[HMS Sidon (P259)|HMS ''Sidon'']] and the [[Russian submarine Kursk (K-141)|Russian submarine ''Kursk'']].<ref>{{cite web |url=https://www.histarmar.com.ar/InfGral/SubmarinosAcc/Peroxide%20Accident%20-%20Walter%20Web%20Site.htm |title=Peroxide Accident — Walter Web Site |publisher=Histarmar.com.ar |access-date=2015-02-14 |archive-url=https://web.archive.org/web/20141210234520/https://www.histarmar.com.ar/InfGral/SubmarinosAcc/Peroxide%20Accident%20-%20Walter%20Web%20Site.htm |archive-date=10 December 2014 |url-status=dead}}</ref> SAAB Underwater Systems is manufacturing the Torpedo 2000. This torpedo, used by the [[Swedish Navy]], is powered by a piston engine propelled by HTP as an oxidizer and [[kerosene]] as a fuel in a bipropellant system.<ref>{{cite journal| vauthors = Scott R |date=November 1997|title=Homing Instincts|journal=Jane's Navy Steam Generated by Catalytic Decomposition of 80–90% Hydrogen Peroxide Was Used for Driving the Turbopump Turbines of the V-2 Rockets, the X-15 Rocketplanes, the Early Centaur RL-10 Engines and is Still Used on Soyuz for That Purpose Today. International|url=https://babriet.tripod.com/articles/art_hominginstinct.htm|access-date=12 May 2007|archive-url=https://web.archive.org/web/20110717102408/https://babriet.tripod.com/articles/art_hominginstinct.htm|archive-date=17 July 2011|url-status=dead}}</ref><ref>{{cite web |url = https://www.nasa.gov/mission_pages/station/structure/elements/soyuz/landing.html |title = Soyuz using hydrogen peroxide propellant |archive-url = https://web.archive.org/web/20130805221214/https://www.nasa.gov/mission_pages/station/structure/elements/soyuz/landing.html |archive-date=5 August 2013 |work = [[NASA]]}}</ref>

===Household use===
[[File:Contact lens case for Hydrogen Peroxide solution showing bubbles.jpg|thumb|170px|right|[[Contact lens]]es soaking in a 3% hydrogen peroxide-based solution. The case includes a catalytic disc which neutralises the hydrogen peroxide over time.]]
Hydrogen peroxide has various domestic uses, primarily as a cleaning and disinfecting agent.

;Hair bleaching
Diluted {{chem2|H2O2}} (between 1.9% and 12%) mixed with [[aqueous ammonia]] has been used to bleach human [[hair]]. The chemical's bleaching property lends its name to the phrase "[[peroxide blonde]]".<ref>{{cite book| vauthors = Lane N |title=Oxygen : the molecule that made the world|year=2003|publisher=Oxford University Press|location=Oxford|isbn=978-0-19-860783-0|page=117|url=https://books.google.com/books?id=ziVk6CI82WgC&q=peroxide+blond&pg=PA117|edition=First issued in paperback, repr.|access-date=12 November 2020|archive-date=13 April 2021|archive-url=https://web.archive.org/web/20210413211129/https://books.google.com/books?id=ziVk6CI82WgC&q=peroxide+blond&pg=PA117|url-status=live}}</ref>
Hydrogen peroxide is also used for [[tooth whitening]]. It may be found in most whitening toothpastes. Hydrogen peroxide has shown positive results involving teeth lightness and chroma shade parameters.<ref>{{cite journal |vauthors = Sulieman M, Addy M, MacDonald E, Rees JS |title = The effect of hydrogen peroxide concentration on the outcome of tooth whitening: an in vitro study |language = English |journal = Journal of Dentistry |volume = 32 |issue = 4 |pages = 295–9 |date = May 2004 |pmid = 15053912 |doi = 10.1016/j.jdent.2004.01.003}}</ref> It works by oxidizing colored pigments onto the [[Tooth enamel|enamel]] where the shade of the tooth may become lighter.{{Explain|reason=Are pigments being oxidized onto the enamel, or pigments being oxidized off the enamel?|date=November 2019}} Hydrogen peroxide may be mixed with baking soda and salt to make a homemade toothpaste.<ref>{{cite web| vauthors = Shepherd S |publisher=FDA Consumer|title=Brushing Up on Gum Disease|url=https://www.fda.gov/bbs/topics/CONSUMER/CON00065.html|access-date=7 July 2007 |archive-url = https://web.archive.org/web/20070514102017/https://www.fda.gov/bbs/topics/CONSUMER/CON00065.html |archive-date = 14 May 2007}}</ref>

;Removal of blood stains
Hydrogen peroxide reacts with blood as a bleaching agent, and so if a blood stain is fresh, or not too old, liberal application of hydrogen peroxide, if necessary in more than single application, will bleach the stain fully out. After about two minutes of the application, the blood should be firmly blotted out.<ref>{{cite web |url=https://www.today.com/home/how-remove-blood-stains-clothes-furniture-t104470 |title=How to remove blood stains from clothes and furniture |vauthors = Gibbs KB |website=Today.com |date=14 November 2016 |access-date=5 August 2021 |url-status=live |archive-date=20 May 2021 |archive-url=https://web.archive.org/web/20210520071431/https://www.today.com/home/how-remove-blood-stains-clothes-furniture-t104470}}</ref><ref>{{cite web |url=https://cleaning.lovetoknow.com/Dried_Blood_Stain_Removal |title=Dried Blood Stain Removal |vauthors = Mayntz M |work=Lovetoknow.com |access-date=5 August 2021 |url-status=live |archive-date=17 August 2021 |archive-url=https://web.archive.org/web/20210817073645/https://cleaning.lovetoknow.com/Dried_Blood_Stain_Removal}}</ref>

;Acne treatment
Hydrogen peroxide may be used to treat [[Acne vulgaris|acne]],<ref>{{cite journal |vauthors = Capizzi R, Landi F, Milani M, Amerio P |title = Skin tolerability and efficacy of combination therapy with hydrogen peroxide stabilized cream and adapalene gel in comparison with benzoyl peroxide cream and adapalene gel in common acne. A randomized, investigator-masked, controlled trial |journal = The British Journal of Dermatology |volume = 151 |issue = 2 |pages = 481–4 |date = August 2004 |pmid = 15327558 |doi = 10.1111/j.1365-2133.2004.06067.x |s2cid = 2611939}}</ref> although [[benzoyl peroxide]] is a more common treatment.

;Oral cleaning agent
The use of dilute hydrogen peroxide as an oral cleansing agent has been reviewed academically to determine its usefulness in treating [[gingivitis]] and [[Dental plaque|plaque]]. Although there is a positive effect when compared with a placebo, it was concluded that [[chlorhexidine]] is a much more effective treatment.<ref>{{Cite journal |last1=Muniz |first1=Francisco Wilker Mustafa Gomes |last2=Cavagni |first2=Juliano |last3=Langa |first3=Gerson Pedro José |last4=Stewart |first4=Bernal |last5=Malheiros |first5=Zilson |last6=Rösing |first6=Cassiano Kuchenbecker |date=2020-10-31 |title=A Systematic Review of the Effect of Oral Rinsing with H2O2 on Clinical and Microbiological Parameters Related to Plaque, Gingivitis, and Microbes |journal=International Journal of Dentistry |volume=2020 |pages=8841722 |doi=10.1155/2020/8841722 |issn=1687-8728 |pmc=7648695 |pmid=33178277 |doi-access=free}}</ref>

===Niche uses===
[[File:Chemiluminescance.JPG|upright|thumb|[[Chemiluminescence]] of [[cyalume]], as found in a glow stick]]
;Horticulture
Some [[horticulture|horticulturists]] and users of [[hydroponics]] advocate the use of weak hydrogen peroxide solution in watering solutions. Its spontaneous decomposition releases oxygen that enhances a plant's root development and helps to treat [[root rot]] (cellular root death due to lack of oxygen) and a variety of other pests.<ref>{{cite web|url=https://www.using-hydrogen-peroxide.com/peroxide-garden.html|title=Ways to use Hydrogen Peroxide in the Garden|website=Using Hydrogen Peroxide|access-date=3 March 2016|archive-url=https://web.archive.org/web/20160304040600/https://www.using-hydrogen-peroxide.com/peroxide-garden.html|archive-date=4 March 2016|url-status=dead}}</ref><ref>{{Cite book |vauthors=Bhattarai SP, Su N, Midmore DJ|title=Oxygation Unlocks Yield Potentials of Crops in Oxygen-Limited Soil Environments |volume=88 |pages=313–377 |year=2005 |doi=10.1016/S0065-2113(05)88008-3 |series=Advances in Agronomy |isbn=978-0-12-000786-8}}</ref>

For general watering concentrations, around 0.1% is in use. This can be increased up to one percent for antifungal actions.<ref>{{cite web| url=https://www.gardeningdream.com/hydrogen-peroxide-for-plants-and-garden-how-much-hydrogen-peroxide-to-use-on-plants/| title=Hydrogen Peroxide for Plants and Garden.| date=7 September 2019| url-status=live| access-date=10 May 2021| archive-date=10 May 2021| archive-url=https://web.archive.org/web/20210510112806/https://www.gardeningdream.com/hydrogen-peroxide-for-plants-and-garden-how-much-hydrogen-peroxide-to-use-on-plants/}}</ref> Tests show that plant foliage can safely tolerate concentrations up to 3%.<ref>{{cite web| url=https://edepot.wur.nl/180309| title=Effect of hydrogen peroxide spraying on Hydrocotyle ranunculoides| url-status=live| access-date=10 May 2021| archive-date=24 March 2020| archive-url=https://web.archive.org/web/20200324072427/https://edepot.wur.nl/180309}}</ref>

;Fishkeeping
Hydrogen peroxide is used in [[aquaculture]] for controlling [[Fish mortality|mortality]] caused by various microbes. In 2019, the U.S. FDA approved it for control of ''Saprolegniasis'' in all coldwater finfish and all fingerling and adult coolwater and warmwater finfish, for control of external [[columnaris]] disease in warm-water finfish, and for control of ''[[Gyrodactylus]]'' spp. in freshwater-reared salmonids.<ref>{{Cite web|url=https://www.fda.gov/animal-veterinary/cvm-updates/fda-approves-additional-indications-35-perox-aid-hydrogen-peroxide-use-certain-finfish/|title=FDA Approves Additional Indications for 35% PEROX-AID (hydrogen peroxide) for Use in Certain Finfish|date=2019-07-26|website=FDA|language=en|access-date=2019-12-19|archive-date=12 December 2019|archive-url=https://web.archive.org/web/20191212181148/https://www.fda.gov/animal-veterinary/cvm-updates/fda-approves-additional-indications-35-perox-aid-hydrogen-peroxide-use-certain-finfish|url-status=live}}</ref> Laboratory tests conducted by fish culturists have demonstrated that common household hydrogen peroxide may be used safely to provide oxygen for small fish. The hydrogen peroxide releases oxygen by decomposition when it is exposed to catalysts such as [[manganese dioxide]].

;Removing yellowing from aged plastics
Hydrogen peroxide may be used in combination with a UV-light source to remove yellowing from white or light grey [[acrylonitrile butadiene styrene]] (ABS) plastics to partially or fully restore the original color. In the [[retrocomputing]] scene, this process is commonly referred to as [[retrobright]].

==Safety==
[[File:Hydrogen peroxide 35 percent on skin.jpg|thumb|alt=Fingertips|Skin shortly after exposure to 35% {{chem2|H2O2}}]]
Regulations vary, but low concentrations, such as 5%, are widely available and legal to buy for medical use. Most over-the-counter peroxide solutions are not suitable for ingestion. Higher concentrations may be considered hazardous and typically are accompanied by a [[safety data sheet]] (SDS). In high concentrations, hydrogen peroxide is an aggressive oxidizer and will corrode many materials, including human skin. In the presence of a [[reducing agent]], high concentrations of {{chem2|H2O2}} will react violently.<ref>{{cite web| url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20050217417.pdf| title=Hydrogen Peroxide Accidents and Incidents: What we can learn from history| publisher=NASA| vauthors = Greene B, Baker D, Frazier W |access-date=6 April 2019| archive-url=https://web.archive.org/web/20190406223209/https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20050217417.pdf| archive-date=6 April 2019| url-status=live}}</ref>
While concentrations up to 35% produce only "white" oxygen bubbles in the skin (and some biting pain) that disappear with the blood within 30–45 minutes, concentrations of 98% dissolve paper. However, concentrations as low as 3% can be dangerous for the eye because of [[oxygen evolution]] within the eye.<ref>see Hans Marquardt, Lehrbuch der Toxikologie</ref>

High-concentration hydrogen peroxide streams, typically above 40%, should be considered hazardous due to concentrated hydrogen peroxide's meeting the definition of a [[United States Department of Transportation|DOT]] oxidizer according to U.S. regulations if released into the environment. The [[United States Environmental Protection Agency|EPA]] Reportable Quantity (RQ) for D001 hazardous wastes is {{convert|100|lb|kg}}, or approximately {{convert|10|USgal|L}}, of concentrated hydrogen peroxide.
[[File:Hydrogen Peroxide Bottle.jpg|thumb|A commercial bottle of H2O2]]
Hydrogen peroxide should be stored in a cool, dry, well-ventilated area and away from any flammable or combustible substances. It should be stored in a container composed of non-reactive materials such as stainless steel or glass (other materials including some plastics and aluminium alloys may also be suitable).<ref>{{cite web|url=https://www.ozoneservices.com/articles/004.htm|title=Material Compatibility with Hydrogen Peroxide|access-date=3 March 2016|archive-url=https://web.archive.org/web/20160304043621/https://www.ozoneservices.com/articles/004.htm|archive-date=4 March 2016|url-status=dead}}</ref> As it breaks down quickly when exposed to light, it should be stored in an opaque container, and pharmaceutical formulations typically come in brown bottles that block light.<ref>{{cite web |url = https://www.hydrogenperoxidemouthwash.org/ |title = Hydrogen Peroxide Mouthwash is it Safe? |access-date = 30 October 2013 |archive-url = https://web.archive.org/web/20131220023527/https://www.hydrogenperoxidemouthwash.org/ |archive-date = 20 December 2013 |url-status = dead}}</ref>

Hydrogen peroxide, either in pure or diluted form, may pose several risks, the main one being that it forms explosive mixtures upon contact with organic compounds.<ref name="osha safety guidelines"/> [[Distillation]] of hydrogen peroxide at normal pressures is highly dangerous. It is corrosive, especially when concentrated, but even domestic-strength solutions may cause irritation to the eyes, [[mucous membrane]]s, and skin.<ref name="hazards">For example, see an {{cite web |url=https://hazard.com/msds/mf/baker/baker/files/h4070.htm |title=MSDS for a 3% peroxide solution |url-status=usurped |archive-url=https://web.archive.org/web/20120415061436/https://hazard.com/msds/mf/baker/baker/files/h4070.htm |archive-date=15 April 2012}}</ref> Swallowing hydrogen peroxide solutions is particularly dangerous, as decomposition in the stomach releases large quantities of gas (ten times the volume of a 3% solution), leading to internal bloating. Inhaling over 10% can cause severe pulmonary irritation.<ref name="atsdr toxic facts">[https://www.atsdr.cdc.gov/toxfaqs/tfacts174.pdf H<sub>2</sub>O<sub>2</sub> toxicity and dangers] {{Webarchive|url=https://web.archive.org/web/20120605150238/https://www.atsdr.cdc.gov/toxfaqs/tfacts174.pdf |date=5 June 2012}} [[Agency for Toxic Substances and Disease Registry]] website</ref>

With a significant vapour pressure (1.2 kPa at 50&nbsp;°C),<ref>CRC Handbook of Chemistry and Physics, 76th Ed, 1995–1996</ref> hydrogen peroxide vapour is potentially hazardous. According to U.S. NIOSH, the [[immediately dangerous to life and health]] (IDLH) limit is only 75 ppm.<ref name="dangerous concentrations">{{cite web|url=https://www.cdc.gov/niosh/idlh/intridl4.html|title=CDC — Immediately Dangerous to Life or Health Concentrations (IDLH): Chemical Listing and Documentation of Revised IDLH Values — NIOSH Publications and Products|access-date=20 October 2018|date=25 October 2017|archive-url=https://web.archive.org/web/20121117012820/https://www.cdc.gov/niosh/idlh/intridl4.html|archive-date=17 November 2012|url-status=live}}</ref> The U.S. [[Occupational Safety and Health Administration]] (OSHA) has established a permissible exposure limit of 1.0 ppm calculated as an 8-hour time-weighted average (29 CFR 1910.1000, Table Z-1).<ref name="osha safety guidelines">{{cite web|url=https://www.osha.gov/SLTC/healthguidelines/hydrogenperoxide/recognition.html|title=Occupational Safety and Health Guideline for Hydrogen Peroxide|url-status=dead|archive-url=https://web.archive.org/web/20130513085633/https://www.osha.gov/SLTC/healthguidelines/hydrogenperoxide/recognition.html|archive-date=13 May 2013}}</ref> Hydrogen peroxide has been classified by the [[American Conference of Governmental Industrial Hygienists]] (ACGIH) as a "known animal carcinogen, with unknown relevance on humans".<ref name="carcinogen">{{cite web|url=https://www2.worksafebc.com/PDFs/regulation/exposure_limits.pdf|title=Threshold Limit Values for Chemical Substances and Physical Agents & Biological Exposure Indices, ACGIH|url-status=dead|archive-url=https://web.archive.org/web/20130602121656/https://www2.worksafebc.com/PDFs/regulation/exposure_limits.pdf|archive-date=2 June 2013}}</ref> For workplaces where there is a risk of exposure to the hazardous concentrations of the vapours, continuous monitors for hydrogen peroxide should be used. Information on the hazards of hydrogen peroxide is available from OSHA<ref name="osha safety guidelines"/> and from the ATSDR.<ref name="atsdr toxic substance">{{cite web|url=https://www.atsdr.cdc.gov/MHMI/mmg174.html|title=ATSDR — Redirect — MMG: Hydrogen Peroxide|access-date=3 March 2016|archive-url=https://web.archive.org/web/20160303221446/https://www.atsdr.cdc.gov/MHMI/mmg174.html|archive-date=3 March 2016|url-status=dead}}</ref>

===Wound healing===
Historically, hydrogen peroxide was used for disinfecting wounds, partly because of its low cost and prompt availability compared to other [[antiseptic]]s.<ref>{{cite journal |vauthors = Wilgus TA, Bergdall VK, Dipietro LA, Oberyszyn TM |title = Hydrogen peroxide disrupts scarless fetal wound repair |journal = Wound Repair and Regeneration |volume = 13 |issue = 5 |pages = 513–9 |year = 2005 |pmid = 16176460 |doi = 10.1111/j.1067-1927.2005.00072.x |s2cid = 1028923}}</ref>

There is conflicting evidence on hydrogen peroxide's effect on wound healing. Some research finds benefit, while other research find delays and healing inhibition.<ref>{{cite journal |vauthors = Urban MV, Rath T, Radtke C |title = Hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>): a review of its use in surgery |journal = Wiener Medizinische Wochenschrift |volume = 169 |issue = 9–10 |pages = 222–5 |date = June 2019 |pmid = 29147868 |doi = 10.1007/s10354-017-0610-2 |s2cid = 35739209}}</ref> Its use for home treatment of wounds is generally not recommended.<ref name="Don't use hydrogen peroxide on wounds">{{cite web|url=https://health.clevelandclinic.org/what-is-hydrogen-peroxide-good-for/|title=Cleveleand Clinic: What Is Hydrogen Peroxide Good For?|date=December 2021 |access-date=25 August 2022}}</ref>
1.5–3% hydrogen peroxide is used as a disinfectant in dentistry, especially in endodotic treatments together with hypochlorite and chlorhexidin and 1–1.5% is also useful for treatment of inflammation of third molars (wisdom teeth).<ref>see e.g. Detlev Heidemann, Endodontie, Urban&Fischer 2001</ref>

===Use in alternative medicine===
Practitioners of [[alternative medicine]] have advocated the use of hydrogen peroxide for various conditions, including [[emphysema]], [[influenza]], [[AIDS]], and in particular [[cancer]].<ref>{{cite book| vauthors = Douglass WC |title=Hydrogen peroxide : medical miracle|date=1995|publisher=Second Opinion Pub.|location=Atlanta, GA|isbn=978-1-885236-07-4}}</ref> There is no evidence of effectiveness and in some cases it has proved fatal.<ref name="largeOral">[https://web.archive.org/web/20020820074823/https://www.sefsc.noaa.gov/HTMLdocs/HydrogenPeroxide3.htm Hydrogen Peroxide, 3%. 3. Hazards Identification] Southeast Fisheries Science Center, daughter agency of [[NOAA]].</ref><ref name="baddrink">{{cite journal |vauthors = |title = Questionable methods of cancer management: hydrogen peroxide and other 'hyperoxygenation' therapies |journal = CA: A Cancer Journal for Clinicians |volume = 43 |issue = 1 |pages = 47–56 |year = 1993 |pmid = 8422605 |doi = 10.3322/canjclin.43.1.47 |s2cid = 36911297 |doi-access = free}}</ref><ref name="snopesH2O2">{{cite web| vauthors = Mikkelson B |title=Hydrogen Peroxide|url=https://www.snopes.com/medical/healthyself/peroxide.asp|website=Snopes.com|date=30 April 2006|access-date=7 July 2007|archive-date=15 February 2022|archive-url=https://web.archive.org/web/20220215183404/https://www.snopes.com/fact-check/hydrogen-peroxide/|url-status=live}}</ref><ref name="lethalInjection">{{cite web |url=https://www.thedenverchannel.com/news/naturopath-sentenced-for-injecting-teen-with-hydrogen-peroxide |title=Naturopath Sentenced For Injecting Teen With Hydrogen Peroxide — 7NEWS Denver |publisher=Thedenverchannel.com |date=2006-03-27 |access-date=2015-02-14 |archive-url=https://web.archive.org/web/20140320012431/https://www.thedenverchannel.com/news/naturopath-sentenced-for-injecting-teen-with-hydrogen-peroxide |archive-date=20 March 2014 |url-status=dead}}</ref>

Both the effectiveness and safety of hydrogen peroxide therapy is scientifically questionable. Hydrogen peroxide is produced by the immune system, but in a carefully controlled manner. Cells called [[phagocyte]]s engulf pathogens and then use hydrogen peroxide to destroy them. The peroxide is toxic to both the cell and the pathogen and so is kept within a special compartment, called a [[phagosome]]. Free hydrogen peroxide will damage any tissue it encounters via [[oxidative stress]], a process that also has been proposed as a cause of cancer.<ref>{{cite journal |vauthors = Halliwell B |title = Oxidative stress and cancer: have we moved forward? |journal = The Biochemical Journal |volume = 401 |issue = 1 |pages = 1–11 |date = January 2007 |pmid = 17150040 |doi = 10.1042/BJ20061131 |s2cid = 850978}}</ref>
Claims that hydrogen peroxide therapy increases cellular levels of oxygen have not been supported. The quantities administered would be expected to provide very little additional oxygen compared to that available from normal respiration. It is also difficult to raise the level of oxygen around cancer cells within a tumour, as the blood supply tends to be poor, a situation known as [[tumor hypoxia]].

Large oral doses of hydrogen peroxide at a 3% concentration may cause irritation and blistering to the mouth, throat, and abdomen as well as abdominal pain, vomiting, and diarrhea.<ref name="largeOral"/> Ingestion of hydrogen peroxide at concentrations of 35% or higher has been implicated as the cause of numerous [[Air embolism|gas embolism]] events resulting in hospitalisation. In these cases, [[Hyperbaric medicine|hyperbaric oxygen therapy]] was used to treat the embolisms.<ref>{{cite journal |vauthors = French LK, Horowitz BZ, McKeown NJ |title = Hydrogen peroxide ingestion associated with portal venous gas and treatment with hyperbaric oxygen: a case series and review of the literature |journal = Clinical Toxicology |volume = 48 |issue = 6 |pages = 533–8 |date = July 2010 |pmid = 20575671 |doi = 10.3109/15563650.2010.492526 |s2cid = 25148041 }}</ref>

[[Intravenous therapy|Intravenous injection]] of hydrogen peroxide has been linked to several deaths.<ref name="deaths">{{cite news| vauthors = Cooper A |title=A Prescription for Death?|work=CBS News|date=12 January 2005|url=https://www.cbsnews.com/news/a-prescription-for-death/|access-date=7 July 2007|archive-url=https://web.archive.org/web/20070717085909/https://www.cbsnews.com/stories/2005/01/12/60II/main666489.shtml|archive-date=17 July 2007|url-status=live}}</ref><ref name="snopesH2O2"/><ref name="lethalInjection"/>
The [[American Cancer Society]] states that "there is no scientific evidence that hydrogen peroxide is a safe, effective, or useful cancer treatment."<ref name="baddrink"/> Furthermore, the therapy is not approved by the U.S. FDA.

===Historical incidents===
* On 16 July 1934, in [[Kummersdorf]], Germany, a propellant tank containing an experimental monopropellant mixture consisting of hydrogen peroxide and [[ethanol]] exploded during a test, killing three people.<ref>{{Cite news|url=https://www.urbex.nl/heeresversuchsstelle-kummersdorf/|title=Heeresversuchsstelle Kummersdorf |date=2008-03-23|work=UrbEx — Forgotten & Abandoned|access-date=2018-06-01|language=en-US|archive-url=https://web.archive.org/web/20180629160812/https://www.urbex.nl/heeresversuchsstelle-kummersdorf/|archive-date=29 June 2018|url-status=live}}</ref>
* During the [[World War II|Second World War]], doctors in [[Nazi concentration camps|German concentration camps]] experimented with the use of hydrogen peroxide injections in the killing of human subjects.<ref>{{cite web |title=The Nazi Doctors: Medical Killing and the Psychology of Genocide |publisher=Robert Jay Lifton |url=https://phdn.org/archives/holocaust-history.org/lifton/LiftonT257.shtml |access-date=26 June 2018 |archive-url=https://web.archive.org/web/20180627005245/https://phdn.org/archives/holocaust-history.org/lifton/LiftonT257.shtml |archive-date=27 June 2018 |url-status=live}}</ref>
* In December 1943, the pilot [[Josef Pöhs]] died after being exposed to the [[T-Stoff]] of his [[Messerschmitt Me 163]].
* In June 1955, Royal Navy submarine [[HMS Sidon (P259)#Accident|HMS ''Sidon'']] sank after leaking high-test peroxide in a torpedo caused it to explode in its tube, killing twelve crew members; a member of the rescue party also succumbed.
* In April 1992, an explosion occurred at the hydrogen peroxide plant at [[Jarrie]] in France, due to technical failure of the computerised control system and resulting in one fatality and wide destruction of the plant.<ref>{{cite web|date=November 2007|title=Explosion and fire in a hydrogen peroxide plant|url=https://www.aria.developpement-durable.gouv.fr/fiche_detaillee/3536_en/?lang=en|archive-url=https://web.archive.org/web/20220214154800/https://www.aria.developpement-durable.gouv.fr/fiche_detaillee/3536_en/?lang=en|archive-date=14 February 2022|publisher=ARIA}}</ref>
* Several people received minor injuries after a hydrogen peroxide spill on board a [[Northwest Airlines]] flight from [[Orlando, Florida]] to [[Memphis, Tennessee]] on 28 October 1998.<ref>{{cite web|title=Accident No: DCA-99-MZ-001|url=https://www.ntsb.gov/investigations/AccidentReports/Reports/HZB0001.pdf|publisher=U.S. National Transportation Safety Board|access-date=30 October 2015|archive-url=https://web.archive.org/web/20151103025027/https://www.ntsb.gov/investigations/AccidentReports/Reports/HZB0001.pdf|archive-date=3 November 2015|url-status=live}}</ref>
* The Russian submarine [[Russian submarine Kursk (K-141)|K-141 ''Kursk'']] sailed to perform an exercise of firing dummy torpedoes at the ''[[Russian battlecruiser Pyotr Velikiy|Pyotr Velikiy]]'', a [[Kirov-class battlecruiser|''Kirov''-class battlecruiser]]. On 12 August 2000, at 11:28 local time (07:28 UTC), [[Kursk submarine disaster|there was an explosion]] while preparing to fire the torpedoes. The only credible report to date is that this was due to the failure and explosion of one of the ''Kursk'''s hydrogen peroxide-fueled torpedoes. It is believed that [[High test peroxide|HTP]], a form of highly concentrated hydrogen peroxide used as propellant for the torpedo, seeped through its container, damaged either by rust or in the loading procedure on land where an incident involving one of the torpedoes accidentally touching ground went unreported. The vessel was lost with all hands.<ref>{{Cite web| vauthors = Mizokami K |date=28 September 2018|title=The True Story of the Russian Kursk Submarine Disaster|url=https://www.popularmechanics.com/military/navy-ships/a23494010/kursk-submarine-disaster/|archive-url= https://web.archive.org/web/20220214155136/https://www.popularmechanics.com/military/navy-ships/a23494010/kursk-submarine-disaster/ |archive-date=14 February 2022}}</ref>
* On 15 August 2010, a spill of about {{convert|30|USgal|L}} of cleaning fluid occurred on the 54th floor of 1515 Broadway, in [[Times Square]], [[New York City]]. The spill, which a spokesperson for the [[New York City Fire Department]] said was of hydrogen peroxide, shut down Broadway between West 42nd and West 48th streets as fire engines responded to the [[HAZMAT|hazmat]] situation. There were no reported injuries.<ref>{{cite news|title=Bleach Spill Shuts Part of Times Square|url=https://www.nytimes.com/2010/08/16/nyregion/16square.html|date=16 August 2010|work=The New York Times| vauthors = Wheaton S |access-date=24 February 2017|archive-url=https://web.archive.org/web/20171201132854/https://www.nytimes.com/2010/08/16/nyregion/16square.html|archive-date=1 December 2017|url-status=live}}</ref>

==See also==
* [[FOX reagent]], used to measure levels of hydrogen peroxide in biological systems
* [[Hydrogen chalcogenide]]
* [[Retrobright]], a process using hydrogen peroxide to restore yellowed [[acrylonitrile butadiene styrene]] plastic
* [[Bis(trimethylsilyl) peroxide]], an aprotic substitute

==References==
{{Reflist}}

'''Bibliography'''
{{Refbegin}}
* {{cite book|title=The Syntheses of Sulphones, Sulphoxides and Cyclic Sulphides|publisher=Wiley |year=1994|isbn=978-0-471-93970-2|pages=109–254, See pp. 112–6 |oclc=521033898 |chapter=3. Synthesis of Sulphoxides |first1=J. |last1=Drabowicz |first2=P. |last2=Kiełbasinski |first3=M. |last3=Mikołajczyk |doi=10.1002/9780470666357.ch3 }}
* {{cite book|title=Chemistry of the Elements|publisher=Butterworth-Heinemann|year=1997|edition=2nd|location=Oxford UK| vauthors = Greenwood NN, Earnshaw A |isbn=1-59124-291-6 |oclc=49708420}} A great description of properties & chemistry of {{chem2|H2O2}}.
* {{cite book|title=Advanced Organic Chemistry|publisher=Wiley|year=1992|edition=4th|location=New York|page=723| vauthors = March J |isbn=0-585-36749-3 |oclc=47010289}}
* {{cite book|title=Kirk-Othmer Encyclopedia of Chemical Technology|publisher=Wiley|year=1995|edition=4th|volume=13 |pages=961–995|chapter=Hydrogen Peroxide| vauthors = Hess WT |isbn=0-471-52686-X |oclc=34412578}}
{{Refend}}

==External links==
{{Commons category}}
{{Wikiversity|Observing the Effects of Concentration on Enzyme Activity}}
* [https://www.periodicvideos.com/videos/mv_hydrogen_peroxide_accident.htm Hydrogen Peroxide] at ''[[The Periodic Table of Videos]]'' (University of Nottingham)
* [https://web.archive.org/web/20051214014658/https://msds.fmc.com/msds/100000010225-MSDS_US-E.pdf Material Safety Data Sheet]
* [https://web.archive.org/web/20160304110351/https://www.atsdr.cdc.gov/tfactsx4.html ATSDR Agency for Toxic Substances and Disease Registry FAQ]
* [https://www.inchem.org/documents/icsc/icsc/eics0164.htm International Chemical Safety Card 0164]
* [https://www.cdc.gov/niosh/npg/npgd0335.html NIOSH Pocket Guide to Chemical Hazards]
* [https://web.archive.org/web/20150502171743/https://www.inclusive-science-engineering.com/hydrogen-peroxide-manufacturing-methods/hydrogenperoxide-by-riedl-pfleiderer/ Process flow sheet of Hydrogen Peroxide Production by anthrahydroquinone autoxidation]
* [https://www.hydrogen-peroxide.us/chemical-properties/Rocketdyne-Hydrogen_peroxide_handbook-1967.pdf Hydrogen Peroxide Handbook by Rocketdyne]
* [https://pubs.acs.org/doi/abs/10.1021/jp962946u IR spectroscopic study J. Phys. Chem.]
* [https://youtube.com/shorts/cF-MUrqVX0A Bleaching action of Hydrogen peroxide] at YouTube

{{Hydrogen compounds}}
{{Antiseptics and disinfectants}}
{{Other dermatological preparations}}
{{Stomatological preparations}}
{{Otologicals}}
{{Hair colors}}
{{Molecules detected in outer space}}
{{oxygen compounds}}
{{Transient receptor potential channel modulators}}
{{Authority control}}

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[[Category:Bleaches]]
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[[Category:1894 introductions]]
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