CuSO47H2O

Copper(II) sulfate pentahydrate, with the chemical formula CuSO4·5H2O, is a well-known inorganic compound. It is commonly encountered as a blue crystalline solid. This hydrated form of copper(II) sulfate is the most frequently seen commercially and in laboratory settings. The compound is derived from copper(II) sulfate, which itself is an ionic compound. In the pentahydrate, five molecules of water are incorporated into the crystal structure for each formula unit of copper(II) sulfate.

CuSO4·5H2O is soluble in water, forming a blue solution. When heated, it loses its water molecules, undergoing dehydration. For example, heating it to around 100°C will yield the anhydrous form, copper(II) sulfate (CuSO4), which is a white powder. Further heating can lead to decomposition.

This compound has a variety of applications. It is used in agriculture as a fungicide, algaecide, and a soil additive to correct copper deficiencies. In industry, it finds use in electroplating, as a mordant in dyeing and printing textiles, and in the preparation of other copper compounds. Historically, it has also been used in pigments and as a catalyst. Due to its toxicity, proper handling and disposal are important.