Sublimation
Examples of sublimation
As mentioned above, (CO2) is a common example of a chemical compound that sublimates at atmospheric pressure—a block of solid CO2 at room temperature and one atmosphere pressure will turn into gas without first becoming a liquid. Iodine is another substance that visibly sublimates at room temperature. In contrast to CO2, though, it is possible to obtain liquid iodine at atmospheric pressure by heating it.
![sublimate.jpg](../images/sublimate.jpg)
Principles of sublimation
Sublimation is a phase transition that occurs at temperatures and pressures below what is called the "triple point" of the substance (see phase diagram). The process is an endothermic change—that is, a change in which heat is absorbed by the system. The enthalpy of sublimation can be calculated as the enthalpy of fusion plus the enthalpy of vaporization.