Ammonium carbonate is a salt with the chemical formula (NH
4)
2CO
3. Commercial samples labelled ammonium carbonate no longer contain this compound, but a mixture that has similar ammonia content. Since it readily degrades to gaseous ammonia and carbon dioxide upon heating, it is used as a
leavening agent and also as
smelling salt. It is also known as
baker's ammonia and was a predecessor to the more modern leavening agents
baking soda and
baking powder. It is a component of what was formerly known as
sal volatile and
salt of hartshorn.