#  Volatile 

 



In planetary science, a volatile is a chemical element or chemical compound with a low boiling temperature. Volatiles are associated with a planet’s or moon's crust and/or atmosphere. Examples include hydrogen, nitrogen, water, carbon dioxide, ammonia, methane, and sulfur dioxide. Volatiles are the first to escape a planetary body’s gravity when energized by an external source (e.g. the body’s host star).