Sodium hexametaphosphate (SHMP) is a hexamer of composition (NaPO3)6. Sodium hexametaphosphate of commerce is typically a mixture of polymeric metaphosphates, of which the hexamer is one, and is usually the compound referred to by this name. It is more correctly termed sodium polymetaphosphate.
A significant use for sodium hexametaphosphate is as a deflocculant in the production of clay-based ceramic particles. It is also used as a dispersing agent to break down clay and other soil types for soil texture assessment.
It is used as an active ingredient in toothpastes as an anti-staining and tartar prevention ingredient.
As a food additive, SHMP is used as an emulsifier. Artificial maple syrup, canned milk, cheese powders and dips, imitation cheese, whipped topping, packaged egg whites, roast beef, fish fillets, fruit jelly, frozen desserts, salad dressing, herring, breakfast cereal, ice cream, beer, and bottled beverages, among other foods, can contain SHMP.
Hexametaphosphoric acid was named (but misidentified) in 1849 by the German chemist Theodor Fleitmann (1828–1904). By 1956, chromatographic analysis of hydrolysates of Graham's salt (sodium polyphosphate) indicated the presence of cyclic anions containing more than four phosphate groups; these findings were confirmed in 1961. In 1963, the German chemists Erich Thilo and Ulrich Schülke succeeded in preparing sodium hexametaphosphate by heating anhydrous sodium trimetaphosphate.
^Van Wazer, John R. Phosphorus and its compounds. New York : Interscience Publishers (1958)
^The Role Of Sodium Hexametaphosphate In The Dissolution Process Of Kaolinite And KaolinF. Andreola; E.Castellini; T.Manfredini; M.Romagnoli. Journal of the European Ceramic Society, Volume 24, Number 7, June 2004.
^Impact Of Dispersants On The Mechanical Strength Development Of Alumina-Spinel Self-Flowing Refractory Castables. Sasan Otroj, Mohammad Reza Nilforushan, Arash Daghighi, Reza Marzban. Ceramics – Silikáty 54 (3) 284–289 (2010)
^Effect Of Adding Sodium Hexametaphosphate Liquefier On Basic Properties Of Calcium Phosphate Cements. S. Hesaraki; A. Zamanian; F. Moztarzadeh. Journal of Biomedical Materials Research Part A. Vol. 88A, No. 2, 2009
^Study Of Clay’s Mineralogy Effect On Rheological Behavior Of Ceramic Suspensions Using An Experimental Design. Afef Jmal Ayadi; Julien Soro; Amel Kamoun; Samir Baklouti. International Journal of Recent Research and Applied Studies 14 (2). February 2013.
^ASTM D422 – 63(2007) Standard Test Method for Particle-Size Analysis of Soils.