Sublimation (phase transition): Difference between revisions

These three cases jointly exhaust the solid space in the phrase diagram. This makemakes sense, after all, technically, all solids sublime (depending mostly on vapour pressure, which is very situational).

One may notice there is a fourth case in the solid space, that is, at the solid-liquid boundary. It is uncertain if the solid is still considereddefined as subliming WHILE melting, and in case it is, it would be subliming gradually, those who know PLEASE CLARIFYrapidly.

AllTechnically, all solids may sublime, though most sublime at extremely low rates under usual conditions that are hardly detectable. At [[standard conditions for temperature and pressure|normal pressures]], most [[chemical compound]]s and [[chemical element|elements]] possess three different states at different [[temperature]]s. In these cases, the transition from the [[solid]] to the [[gas]] state requires an intermediate liquid state. The pressure referred to is the ''[[partial pressure|partial]]'' [[partial pressure|pressure]] of the substance, not the ''total'' (e.g. atmospheric) pressure of the entire system. Thus, any solid can sublime if its [[vapour pressure]] is higher than the surrounding partial pressure of the same substance, and in some cases, sublimes at an appreciable rate (e.g. water ice just below 0 °C).

For clarification, a distinction between the two corresponding cases is needed. With reference to a [[phase diagram]], the sublimation that occurs left of the solid-gas boundary, the triple point or the solid-liquid boundary (corresponding to evaporation in vaporization) may be called ''gradual sublimation''; and the substance ''sublimes gradually'', regardless of rate. The sublimation that occurs at the solid-gas boundary (critical sublimation point) (corresponding to boiling in vaporization) may be called ''rapid sublimation'', and the substance ''sublimes rapidly''. The words "gradual" and "rapid" have acquired special meanings in this context and no longer describe the rate of sublimation.{{cn|date=April 2024}}<!-- This distinction is used only on this page and nowhere else, to minimize confusion. If there is a better distinction, change it along with the examples. If this violates the policy of Wikipedia, please delete this paragraph and nothing else, and if possible, also provide a better solution. -->

[[Snow]] and [[ice]] sublime gradually at temperatures below the solid-liquid boundary (melting point) (generally 0&nbsp;°C), and at partial pressures below the triple point pressure of {{convert|612|Pa|atm|abbr=on}}, at a low rate.<ref>{{cite journal |last=Fassnacht |first=S. R. |year=2004 |title=Estimating Alter-shielded gauge snowfall undercatch, snowpack sublimation, and blowing snow transport at six sites in the coterminous USA |journal=Hydrol. Process. |doi=10.1002/hyp.5806 |bibcode=2004HyPr...18.3481F |volume=18 |issue=18 |pages=3481–3492|s2cid=129927018 }}</ref> In [[freeze-drying]], the material to be dehydrated is frozen and its water is allowed to sublime under reduced pressure or vacuum. The loss of snow from a [[snowfield]] during a cold spell is often caused by sunshine acting directly on the upper layers of the snow. Sublimation of ice is a factor to the erosive wear of [[glacier ice]], also called [[ablation]] in [[glaciology]].{{citation needed|date=October 2021}}

}}</ref> at a high rate, with the critical sublimation point at around 80{{nbsp}}°convert|80|C or 176{{nbsp|F}}°F.<ref>