# Why is anhydrous copper sulfate a white powder, while CuSO_4*5H_2O a blue crystal?

##### 1 Answer
Jul 31, 2017

Because the waters of hydration are incorporated into the crystal structure of the solvate.

#### Explanation:

$\text{Copper sulfate pentahydrate}$, $C u S {O}_{4} \cdot 5 {H}_{2} O$, gives beautiful macroscopic crystals.....

The water molecules are actually incorporated into the coordination sphere of the copper ion. Dry the crystals thoroughly (no easy task), and you are left with anhydrous $C u S {O}_{4}$, a white salt.