Sodium hexametaphosphate is the colorless glassy solid with the molecular formula (NaPO3)5 and its molecular weight 503.87. Its melting point is 616°C (it decomposes at 616°C ), and the refractive index is 1.482±0.002. It is insoluble in organic solvents and soluble in water, but dissolves very slowly at low temperature, and dissolves quickly in warm water at 30 to 40 °C.

The water-soluble liquid is weakly acidic (pH=6.0～6.8), it is used as a dispersant for non-weighted water-based mud, and removes Ca2+ and Mg2+ ions by forming chelated phosphates. Therefore, it can effectively prevent the mud flocculation caused by Ca2+ and Mg2+, and is very effective against cement invasion and gypsum invasion in mud treatment. But it is not suitable for high temperature, high salt and high calcium conditions. Its main function in industry is to soften hard water.