Chemicals in a solution reacting to form a solid is known as a precipitation reaction. The solid resulting from a precipitation reaction is known as the ‘precipitate’ and the chemical is the ‘precipitant’. The leftover liquid free from precipitate is called the ‘supernate’.
Precipitation reactions have a wide ranging usage, varying from removing salts from water, making pigments, and extracting minerals. The vibrant colours of precipitates can sometimes be used to identify their polarity, defining whether they are cations or anions.
A process called ‘precipitate ageing’ is used in order to create bigger and cleaner particles by leaving precipitate at a higher temperature in its solution.