Sodium Hexametaphosphate - (NaPO3)6

What is Sodium Hexametaphosphate?

Sodium Hexametaphosphate is also called as Calgon. The formula for Sodium Hexametaphosphate is (NaPO3)6. It is a gathering of sodium polyphosphate polymers based on repeating NaPO3 units. It is a water dissolvable polyphosphate glass that comprises of circulation of polyphosphate chain lengths. Sodium hexametaphosphate is a complex phosphate glass produced by a thermal process from soda ash and food-grade phosphoric acid.

Table Of Contents

Sodium Hexametaphosphate Structure – (NaPO3)6

Sodium Hexametaphosphate – NaPO36

Chemical information of Sodium Hexametaphosphate – (NaPO3)6

(NaPO3)6 Sodium Hexametaphosphate
Density 2.48 g/cm³
Molecular weight/ Molar mass 611.77 g/mol
Boiling point 1,500 °C
Melting point 628 °C
Chemical formula Na6P6O18

Physical Properties of Sodium Hexametaphosphate – (NaPO3)6

Odour Odourless
Appearance White crystals
Refractive index 1.482
pH 8.6
Solubility Soluble in water, insoluble in organic solvents.

Chemical Properties of Sodium Hexametaphosphate – (NaPO3)6

  • When Sodium Hexametaphosphate is added to water normally deposits CaCO3 scale, when made more alkaline or when heated the complex phosphate inhibits precipitation.
  • Sodium Hexametaphosphate is advantageous where the boiler water naturally tends to become too alkaline because this reduces excess alkalinity by reversion in the boiler to an acid orthophosphate.

Uses of Sodium Hexametaphosphate – (NaPO3)6

  • Used as a surfactant, emulsifier, suspending agent, dispersing agent and as buffer.
  • Industrial uses include clay processing, drilling fluids and cleaning products which stick together and form clumps.
  • Used in water treatment, when added to a municipal or industrial water systems it helps to reduce scale formation, corrosion, and biofilm formation in pipes and other equipment.

Frequently Asked Questions – FAQs


What is sodium hexametaphosphate used for?

Sodium hexametaphosphate is used as a surfactant, emulsifier, suspending agent, and dispersing agent, is a clean, non-toxic phosphate, that is widely used in the food industry and the chemical industry. It can be used as a chelating reagent for metal ions, an adhesive, and a swelling reagent.


Is sodium hexametaphosphate safe to consume?

Yes, its safety when used as a food additive has been approved by the U.S. Food and Drug Administration (FDA).


Is Sodium Hexametaphosphate covalent or ionic?

Sodium hexametaphosphate is an ionic compound.


Is sodium hexametaphosphate a preservative?

Sodium hexametaphosphate (SHMP) is a widely used industrial preservative commonly found in children’s drinks.


What is the correct formula of Sodium Hexametaphosphate?

The correct formula of Sodium Hexametaphosphate is (NaPO3)6

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