Barium Ba (Element 56) of Periodic Table

56 Ba (Barium)

It is a soft, metallic element (Pure barium is of silvery-white).
The metal oxidizes very easily in air, so it should be stored in mineral oil or other suitable oxygen-free liquids to prevent from contact with air.
It is decomposed by water or alcohol.
Barium forming often poisoning compounds by reacts with almost all non-metals.
Commonly barium sold is about 99% pure, with main impurities strontium (upto 0.8%) and calcium (upto 0.25 %).

 
Identity
CAS Number: CAS7440-39-3
CID Number:  CID5355457
DOT Hazard Class:  4.3
DOT Number:  1400
RTECS Number:  RTECSCQ8370000

Basic Properties of Barium

Pronunciation:  Bair-ee-am
Appearance:  Silvery gray; with pale yellow tint
Mass Number:  137
Standard Atomic weight: 137.327  g/mol
Atomic number (Z):  56
Electrons: 56
Protons:  56
Neutrons:  81

Group:  2
Period:  6
Block:  s
Element category:  Alkaline earth metals
Electrons per shell:  K2, L8, M18, N18, O8, P2
Electron configuration:  1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶4d¹⁰5s²5p⁶6s²

Thermal Properties of Barium

Phase:  Solid
Melting point:  1000 K (727 ^oC, 1341 ^oF)
Boiling point:   2118 K (1845 ^oC, 3353 ^oF)
Fusion heat:  7.12 kJ/mol
Vaporization heat:  142 kJ/mol
Molar heat capacity:  28.07 J/(mol.K)
Thermal expansion:  20.6 μm/(m∙K)
Thermal conductivity:  18.4 W/(m∙K)

Electrical properties of Barium

Electrical conductivity: 2.9×10⁶ S/m
A Electrical resistivity:  332 nΩ∙m
A Electrical type:  Conductor

Magnetic Properties of Barium

A Magnetic type:  Paramagnetic
Magnetic susceptibility (x_mol):  +20.6×10^-6 cm³/mol
Volume magnetic susceptibility:  0.00003966
Mass magnetic susceptibility:  11.3×10^-9 m³/kg
Molar magnetic susceptibility:  1.552×10^-9 m³/mol

Physical Properties of Barium

Density:  3.51 g/cm³ (In solid)  3.338 g/cm³ (In Liquid)
Molar volume:  0.00003912 m³/mol
Young’s modulus:  13 GPa
Shear modulus:  4.9 GPa
Mohs Hardness:  1.25
Bulk modulus:  9.6 GPa
Sound Speed:  1620 m/s

Atomic Properties of Barium 

Oxidation states:  +2, +1
Valence Electrons:  6s²
Ion charge:  Ba²⁺
Ionization Potential of an atom:  5.19
Ionization energies:  1st: 502.9 kJ.mol 2nd: 965.2 kJ/mol 3rd: 3600 kJ/mol
Ionic radius:   135 pm
Atomic radius:  268 pm (Van der Waals)
Covalent radius:  215±11 pm
Filling Orbital:  6s²
Crystal structure:  Body-centered cubic
Lattice angles:  π/2, π/2, π/2
Lattice constant:  502.8, 502.8, 502.8 pm
Grid parameters:  5.020 Å
Space Group Name:  lm_3m
Space Group Number:  229

Reactivity of Barium

Electronegativity:  Pauling scale: 0.89
Valence:  +2
Electron affinity:  13.95 kJ/mol

Nuclear Properties of Barium

Half Life:  Stable (Infinity)
Lifetime:  Stable (Infinity)
Quantum Number:  ¹S₀
Neutron cross section (Brans):  1.3
Neutron Mass Absorption:  0.00027
Isotopes:  130_Ba 132_Ba 133_Ba 134_Ba 135_Be 136_Ba 137_Ba 138_Ba
 

Isotope	Abundance (%)	Atomic Mass g/mol	Half Life (t1/2)
130Ba	0.11	129.906	(0.5-2.7)x1021 y
132Ba	0.10	131.905	Stable
133Ba	Syn	–	10.51
134Ba	2.42	133.905	Stable
135Ba	6.59	134.906	Stable
136Ba	7.85	135.905	Stable
137Ba	11.23	136.906	Stable
138Ba	71.70	137.905	Stable

 Chemical Reactions

The metal once ignited, burns readily  to form Barium oxide and Barium nitride:
2 Ba(s) + O₂(g) → 2BaO(s)
Ba(s) + O₂(g) → BaO₂(s)
3Ba(s) + N₂(g) → Ba₃N₂(s)
Barium Reactions with water and alcohols are very exothermic and release hydrogen gas (R is alkyl group or a hydrogen atom)
Ba + 2 ROH → Ba(OR)₂ + H₂↑
Reacts Readily with water (slower than radium and quicker than strontium) to form Barium (lll) hydroxide and hydrogen gas:
Ba (s) + 2 H₂O (l) → Ba(OH)₂ (aq) + H₂ (g)
React with Hydrogen (forming Barium hydride):
Ba(s) + H₂(g) → BaH₂ (s)
Barium reacts with hydrochloric acid and form a barium chloride:
Ba (s) + 2 HCl (aq) → Bacl₂ (aq) + H₂ (g)
 
Pure barite reduced by carbon to barium sulfide:
BaSO₄ + 2 C → BaS + 2 CO₂↑
The metal is produced by reduction with Aluminium:
3 Bao + 14 Al → 3 BaAl₄ + Al₂O₃
Intermetallic compound (BaAl₄) reacted with barium oxide to produce the metal.
8 BaO + BaAl₄ → Ba↑ + 7 BaAl₂O₄
Remaining barium oxide reacts with the formed aluminium oxide (Al₂O₃):
BaO + Al₂O₃ → BaAl₂O₄
Overall reaction is:
4 BaO + 2 Al → 3 Ba↑ + BaAl₂O₄
(Barium vapour condensed and packed into molds in environment of argon)

Barium History

Naming: Greek: Barys (heavy or dense)
Discovery:  Carl Wilhelm Scheele (1772)
First isolation:  Humphry Davy (1808) in London

Barium Uses

The most important barium compounds are chloride, carbonate, sulfate, peroxide, nitrate, and chlorate.
 
Barium alloys with calcium, silicon, manganese, and aluminum as high-grade steel deoxidizers.
Barium is used in barium-nickel alloys for spark-plug electrodes.
Barium-aluminium alloyed is used to remove unwanted gases (gettering) from vacuum tubes, such as TV picture tubes
 
Barium compounds are used as a weighing agent in drilling fluids for oil and gas wells, and also used to in making paint, glass, tiles, bricks, and rubber.
 
‘barium meal’ or ‘barium enema’ known as Barium Sulphate.
Barium sulfate is insoluble and it has low toxicity, so it can be given sometimes  to patients suffering from digestive disorders.
Due to high opacity, It is also used in X-rays diagnostic work. Because it  is a contrast agent that is used to better visualize the gastro-intestinal tract via radiology. where, the X-rays show a complete picture of the gastro-intestinal tract.
The impure barium sulfide phosphoresces after exposure to the light.
 
Barium carbonate has been used in the past as a rat poison, while the nitrate and chlorate give fireworks a green colour.

Biological role
It is toxic.
All barium compounds that are water or acid soluble are poisonous
Higher doses affect the nervous system, causing cardiac irregularities, anxiety, tremors, shortness of breath, weakness, and paralysis.

Abundance of Barium

It is found only in combination with other elements, never found in pure form due to its reactivity.
Its found in Barite (barium sulfate BaSO₄) and witherite (Baium carbonate BaCO₃)
 
The metal is prepared by electrolysis of the molten barium chloride, or by heating barium oxide with aluminium.
 
Annual world wide production is around 6,000,000 tons.
5×10^-7% (In Universe)
1.7×10^-5% (In Meteorites)
1×10^-7% (In Sun)
0.0008% (In Earth’s Crust)
4.5×10^-11% (In Oceans)

World’s Top 3 producers of Barium

1) China
2) India
3) USA

World’s Top 3 Reserve holders of Barium

1) China
2) India
3) Algeria

#barium

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