Copper(II) sulfate, also known as copper sulphate, are the inorganic compounds with the chemical formula CuSOₓ, where x can range from 0 to 5. The pentahydrate is the most common form. Older names for this compound include blue vitriol, bluestone, vitriol of copper, and Roman vitriol. This chemical, Cupric sulfate, is a medium sized crystal with the chemical formula CuSO4•5H2O.