Sublimation is a process through which it passes from a solid state of matter, gases , without transiting the liquid state at all. In that sense it is the inverse process to inverse sublimation or deposition.
It is a matter of a much less frequent transformation of matter than evaporation (liquid to gas) or fusion (solid to gas), which usually requires the injection of heat energy until a variable point is reached according to the nature of the matter (called sublimation point ).
It is often used in laboratories as a method of phase separation .
- Dry ice . Carbon dioxide (CO 2 ) can be liquefied first and then frozen to make dry ice. And this, at room temperature, recovers its original gaseous form.
- Polar evaporation . Since at the terrestrial poles (Arctic and Antarctic) the water is frozen even below 0 ° C, part of it sublimates back into the atmosphere.
- Snow in the mountains . The perpetual snow on the mountain tops is preserved in a semi-solid state, from which it can once again be vapor without having to go through its liquid state, simply sublimating.
- The disappearance of naphthalene . Made of benzene rings, this material is used as a preservative for clothing, by repelling moths and other animals that devour it. Their typical white balls disappear by themselves as they go from solid to gaseous state.
- Arsenic treatment . When carried above 615 ° C, arsenic, traditionally solid, loses its solid form and becomes a highly poisonous gas.
- Iodine treatment . Subjected in the laboratory to heating, the iodine crystals become a gas with a characteristic purple color.
- Obtaining sulfur flower . This is the name given to the presentation in the form of very fine dust of sulfur, extremely useful in industrial processes. This is obtained through the heating of the element, which is sublimated under certain conditions.
- Sublimation of aluminum . In certain specific industrial processes, the sublimation of aluminum occurs, which requires raising this material to more than 1000 ° C and subjecting it to certain pressure conditions that prevent its fusion at lower temperatures.
- Purification of materials . In certain alloys or homogeneous mixtures that are normally in the form of solids (compounds with iodine, with sulfur, etc.) the mixture can be purified by sublimation, heating it under controlled conditions. It is a process similar to the distillation of liquids: one solid will be sublimated and the other will remain in the container.
- The “tail” of comets . Comets are traveling rocks that, when approaching the sun, are heated and much of the CO 2 that has frozen is sublimated, generating its typical visible wake.
- Frost formation . At very cold ambient temperatures, the water vapor will undergo a process of reverse sublimation or deposition, and will form ice crystals in the glasses and surfaces, known as “frost.”
- Planetary accretion . The formation of the solid matter of the planets and other astronomical objects obeys to the inverse sublimation of the gases released in Supernovas, whose eventual pressure and temperature can force to become solid matter.
- Corrosive sublimate of gases . Some metallic gases such as mercuric chloride can sublimate inversely in the presence of other metals, by a very frequent degradation procedure in alchemical operations.
- Obtaining CO 2 by benzoic acid . The carbon dioxide present in this solid compound is released in the form of gases when subjected to certain temperatures, without going through the liquid stage first.
- Flavoring tablets . Used in bathrooms and environments that are desired to be perfumed, they work from the gradual transformation of solid to gas, allowing to cover the entire space in which they are contained.