Hydrogen Chloride - HCl, anhydrous hydrochloric acid. Its molecular weight is 36.47 g/mol; it is a colorless, corrosive gas. Hydrogen chloride is a covalent bonded nonflammable gas and ionizes almost completely when dissolved in water. When dissolved in water, hydrogen chloride forms a strong acid, hydrochloric acid. In the stratosphere, HCl acts as a reservoir species temporarily removing chlorine radicals from a catalytic ozone destruction cycle. (See ozone and chlorine.)
[The journal of Physical Chemistry; v 98; p 2836; 1994]
[New Scientist; v 137; p 19; 1993.] 
Atmospheric Chemistry Glossary