Hydrate Isomerism
Isomerism arising from water molecules occupying either the coordination sphere or lattice positions outside it.
Unit
Dimensionless
In depth
A special case of ionisation isomerism in which water is the exchanging species. The isomers differ in colour, in the amount of water lost on gentle drying, and in the number of ions produced on dissolution.
Examples in the real world
The violet [Cr(H₂O)₆]Cl₃, the green [Cr(H₂O)₅Cl]Cl₂·H₂O and the darker green [Cr(H₂O)₄Cl₂]Cl·2H₂O.