Water of crystallisation

Hydrated describes a crytalline compound containing water molecules.

Anhydrous describes a substance that contains no water molecules. 

The water of crystallisation describes the water molecules that form an essential part fo the crystalline structure of a compound. 

The empirical formula for a hydrated compound is written so that the formula of the compound is separated from the water of crystallisation by a dot. 

The number of hydrogen ions is used to work out the water of…