Question

Why does hydrated copper sulphate exist with 5H2O rather than 6? Copper complexes have 6 H2O ligands.

Answer 1

That's a tough question.
Someone from my school told me that it needs 5 bonds to a full outer shell

But Cu(II) has 2 valence electrons, it wants 8 so it would need 6 to get a full outer shell.

Weird stuff. Maybe someone with knowledge of quantum mechanics knows the answer.

Answer 2

Thanks anyway. I can't figure it out.

Answer 3

copper sulphate dissolved in water CAN form hexaquacopper (II) and I believe it does exist.

Answer 4

You might be able to explain this using M.O. theory. Just as @thomaster this is more quantum quantum approach. Using SALC's, symmetry table, and so forth.