Copper (II) sulfate, also known as cupric sulfate or copper sulphate, is the inorganic compound with the chemical formula CuSO4.

This salt exists as a series of compounds that differ in their degree of hydration. Theanhydrous form is a pale green or gray-white powder, whereas the pentahydrate (CuSO4·5H2O), the most commonly encountered salt, is bright blue. Copper (II) sulfateexothermically dissolves in water to give the aquo complex [Cu(H2O)6]2+, which hasoctahedral molecular geometry and is paramagnetic. Other names for copper(II) sulfate are "blue vitriol" and "bluestone