Initial language selection is based on your web browser preferences.
**Molecular formula (copper sulfate):** CuSO₄
**Molecular formula (cupric sulfate):** CuSO₄·5H₂O
**Molar mass:** 159,610 g/mol (anhydrous)
**Molar mass:** 249,686 g/mol (pentahydrate)
**Information:** Copper sulfate in the anhydrous state has the appearance of a white powder. It is an ionic compound containing a copper Cu²⁺ cation and a sulphate anion SO₄²⁻. When accepting water it changes colour from white to blue. It crystallizes from the aqueous solution as a bluestone (copper sulfate pentahydrate CuSO₄·5H₂O) which forms azure blue crystals.
**Use:** Anhydrous copper sulphate is used to detect water. Bluestone is used to produce pest killers (wood impregnation) and algae in swimming pools.