Magnesium nitrate refers to inorganic compounds with the formula Mg(NO3)2(H2O)x, where x = 6, 2, and 0. All are white solids. The anhydrous material is hygroscopic, quickly forming the hexahydrate upon standing in air. All of the salts are very soluble in both water and ethanol.Magnesium nitrate hexahydrate is a crystalline, water-soluble salt that contains magnesium and nitrate. It’s used in chemical production, analytical chemistry, and laboratory synthesis.