Sublimation (phase transition)

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Dark green crystals of nickelocene, sublimed from the round-bottom flask and freshly deposited on a cold finger



The term sublimation refers to a physical change of state and is not used to describe transformation of a solid to a gas in a chemical reaction. For example, the dissociation on heating of solid ammonium chloride into hydrogen chloride and ammonia is not sublimation but a chemical reaction. Similarly the combustion of candles, containing paraffin wax, to carbon dioxide and water vapor is not sublimation but a chemical reaction with oxygen.

Sublimation requires additional energy and is an endothermic change. The enthalpy of sublimation (also called heat of sublimation) can be calculated by adding the enthalpy of fusion and the enthalpy of vaporization.



Carbon dioxide[edit]

Small pellets of dry ice subliming in air





Naphthalene, an organic compound commonly found in pesticide such as mothball also sublimes. It sublimes easily because it is made of non-polar molecules and has van der Waals intermolecular forces. Naphthalene is a solid that sublimes at standard atmospheric temperature[5] with the sublimation point at around 80˚C or 176˚F.[6] At low temperature, its vapour pressure is high enough, 1 mmHg at 53˚C,[7] to make the solid form of naphthalene evaporate into gas. On the cool surface, the sublimated vapour will be solidified to form a needle-like crystal.

Solid compound of naphthalene sublimed to form a crystal-like structure on the cool surface.

Other substances[edit]


Iodine produces fumes on gentle heating. It is possible to obtain liquid iodine at atmospheric pressure by controlling the temperature at just above the melting point of iodine. In forensic science, iodine vapor can reveal latent fingerprints on paper.[8] Arsenic can also sublime at high temperatures.

Sublimation purification[edit]

Crystals of ferrocene after purification by vacuum sublimation


Historical usage[edit]


And Sublimations we make for three causes,
The first cause is to make the body spiritual.
The second is that the spirit may be corporeal,
And become fixed with it and consubstantial.
The third cause is that from its filthy original.
It may be cleansed, and its saltiness sulphurious
May be diminished in it, which is infectious.

Sublimation predictions[edit]


See also[edit]

Pfeil SO.svg
Solid Liquid Gas Plasma
From Solid Solid-solid transformation Melting Sublimation
Liquid Freezing Boiling / evaporation
Gas Deposition Condensation Ionization
Plasma Recombination / deionization


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  3. ^ Sublime. Retrieved on 2015-11-25.
  4. ^ Fassnacht, S. R. (2004). "Estimating Alter-shielded gauge snowfall undercatch, snowpack sublimation, and blowing snow transport at six sites in the coterminous USA" (PDF). Hydrol. Process. 18: 3481–3492. Bibcode:2004HyPr...18.3481F. doi:10.1002/hyp.5806. [dead link]
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  12. ^ DiBernard, Barbara (1980). Alchemy and Finnegans wake. SUNY Press. p. 57. ISBN 0873953886. 
  13. ^ Ripley, George (1591). Compound of Alchemy.
  14. ^ Gavezzotti, A. (1997). Theoretical Aspects and Computer Modeling of the Molecular Solid State. Chichester: Wiley and Sons. 
  16. ^ McDonagh, James; Palmer, David S.; Van Mourik, Tanja; Mitchell, John B. O. (17 October 2016). "Are The Sublimation Thermodynamics of organic molecules predictable?". Journal of Chemical Information and Modeling. doi:10.1021/acs.jcim.6b00033. ISSN 1549-9596.