Characters. - Deep blue prismatic crystals, very deliquescent, highly corrosive. With one-third of its weight of water it forms at a temperature below 70° F. (21.1° C), tabular crystals;

Cu(NO3)2.6H2O. With a very little more water, added directly or absorbed from the air, it yields a styptic, caustic, corrosive fluid.

Reactions. - The diluted aqueous solution is only faintly acid to litmus; it gives the reactions of copper and a nitrate (p. 594).