what are hydrates crystals
Many compounds are found in crystal form with water attached. These compounds are called hydrates and the crystals with water attached are called hydrated crystals.The formula for the hydrated crystal tells how many water molecules are attached to each formula unit of crystal.For example, hydrated calcium nitrate is written: Ca(NO3)2 (4 H2O and is called calcium nitrate tetrahydrate.he formula for the hydrated crystal tells how many water molecules are attached to each formula unit of crystal. For example, hydrated calcium nitrate is written: Ca(NO3)2 (4 H2O and is called calcium nitrate tetrahydrate.