It is a colourless solid that finds specialised applications in food and construction industries: it is used as a phosphorylating agent for ascorbic acid to stabilize vitamin C mixtures against thermal decomposition; in the construction industry, sodium trimetaphosphate is used to prevent the shrinkage of gypsum plaster boards (US Pat.

[2] Although drawn with a particular resonance structure, the trianion has high symmetry.

[3] Trisodium trimetaphosphate is produced industrially by heating sodium dihydrogen phosphate to 550 °C, a method first developed in 1955:[5] The trimetaphosphate dissolves in water and is precipitated by the addition of sodium chloride (common ion effect), affording the hexahydrate.

[6] STMP can also prepared by heating samples of sodium polyphosphate,[2] or by a thermal reaction of orthophosphoric acid and sodium chloride at 600°C.

[7][8] Hydrolysis of the ring leads to the acyclic sodium triphosphate: The analogous reaction of the metatriphosphate anion involves ring-opening by amine nucleophiles.