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In astrophysical usage (e.g., planetary science, such as theories of planet formation) volatile material (often shortened to volatile) is material that remains non-solid at relatively low temperatures, thus turns solid relatively late if it is cooling. Material that is not volatile (i.e., that turns solid at a higher temperature) is called refractory material. The material in question can be a pure chemical element (volatile element or refractory element), or it can be a compound (volatile compound or refractory compound). A commonly-used threshold between volatile and refractory is whether it turns solid below/above 1300 K. When a planet is forming, cooling from a high temperature, volatiles remain gaseous longer and have more time to escape, a reason for low abundances later on. Volatiles include water, methane, molecular hydrogen, and the familiar molecules of the Earth's atmosphere.
Astrophysics uses the term condensation and condensation temperature to refer to the material becoming solid as it cools whereas the word condensation typically refers to gas cooling and turning to liquid.