Blue vitriol or copper sulphate pentahydrate} has a molecular formula of CuSO₄.5H₂O of the five water molecules associated with this structure, only four are directly replaceable by NH₃, which suggest that water molecule is somehow differently attached.

Blue vitriol is CuSO₄.5H₂O and it has all types of bonds.

The structure of CuSO₄.5H₂O in the solid-state is shown above

The Cu²⁺ ions are attracted towards SO₄^2– ​ions not only by ionic interactions (electrovalent) but also by coordinate covalent bonds.

The Cu²⁺ ions form coordinate covalent bonds with water as well as sulfate ions.

There are covalent bonds in water and sulfate ions.