Know the blue dragonfly--copper sulfate pentahydrate

Copper sulfate pentahydrate, commonly known as blue vitriol, copper vitriol or alum, as a chemical equation CuSO4 · 5H2O, blue crystals. Anhydrous copper sulfate is stable under normal temperature and pressure, does not deliquesce, and gradually weathers in dry air. When heated to 45 ° C, it -----