Sodium trimetaphosphate

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Sodium trimetaphosphate[1]
Sodium trimetaphosphate.png
Identifiers
CAS number 7785-84-4 YesY
PubChem 24579
EC number 232-088-3
Jmol-3D images Image 1
Properties
Molecular formula Na3P3O9
Molar mass 305.885 g/mol
Appearance colorless or white crystals
Density 2.49 g/cm3 (anhydrous)
1.786 g/cm3 (hexahydrate)
Melting point 53 °C (hexahydrate, decomp. to anyhdrous)
Solubility in water 22 g/100 mL
Solubility insoluble in alcohol
Refractive index (nD) 1.433 (hexahydrate)
Structure
Crystal structure triclinic (hexahydrate)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

Sodium trimetaphosphate (also STMP), with formula Na3P3O9, is a metaphosphate of sodium. It has the empirical formula NaPO3. It is the sodium salt of trimetaphosphoric acid. It is a colourless solid that finds specialised applications in food and construction industries. STMP is prepared by heating sodium polyphosphate at a few hundred degrees. [2]

Although drawn with a particular resonance structure, the trianion has D3d symmetry.

References[edit]

  1. ^ Lide, David R. (1998). Handbook of Chemistry and Physics (87 ed.). Boca Raton, FL: CRC Press. pp. 4–86. ISBN 0-8493-0594-2. 
  2. ^ Klaus Schrödter, Gerhard Bettermann, Thomas Staffel, Friedrich Wahl, Thomas Klein, Thomas Hofmann "Phosphoric Acid and Phosphates" in Ullmann’s Encyclopedia of Industrial Chemistry 2008, Wiley-VCH, Weinheim. doi:10.1002/14356007.a19_465.pub3