cas;no:7778-77-0 properties: white or colorless crystal, easily soluble in water, relative density at 2.338, melting point at 252.6 , and ph value of 1% solution is 4.5. uses: used to manufacture metaphosphate in medical or food industry. used as a high effective k and p compound fertilizer. it contains totally 86% fertilizer elements, used as a basic raw material for n, p and k compound fertilizer.