World Library  
Flag as Inappropriate
Email this Article

Sodium hexametaphosphate

Article Id: WHEBN0000629218
Reproduction Date:

Title: Sodium hexametaphosphate  
Author: World Heritage Encyclopedia
Language: English
Subject: Metaphosphate, Calgon, Sequestrant, Disodium pyrophosphate, Eukanuba
Collection: Glass Compositions, Phosphates, Photographic Chemicals, Sodium Compounds, Water Treatment
Publisher: World Heritage Encyclopedia

Sodium hexametaphosphate

Sodium hexametaphosphate[1]
Skeletal formula of sodium hexametaphosphate
Other names
Calgon S

Glassy sodium
Graham's salt
Hexasodium metaphosphate

Metaphosphoric acid, hexasodium salt
ChemSpider  N
EC number 233-343-1
Jmol-3D images Image
Molar mass 611.7704 g mol−1
Appearance White crystals
Odor odorless
Density 2.484 g/cm3
Melting point 628 °C (1,162 °F; 901 K)
Boiling point 1,500 °C (2,730 °F; 1,770 K)
Solubility insoluble in organic solvents
Main hazards Irritant
Safety data sheet
S-phrases S24/25
Lethal dose or concentration (LD, LC):
LD50 (Median dose)
3.053 g kg−1
Related compounds
Other anions
Trisodium phosphate
Tetrasodium pyrophosphate
Pentasodium triphosphate
Related compounds
Sodium trimetaphosphate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
 N  (: Y/N?)

Sodium hexametaphosphate (SHMP) is a hexamer of composition (NaPO3)6.[2] 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.


  • Uses 1
    • Food additive 1.1
  • Preparation 2
  • Reactions 3
  • References 4
  • External links 5


SHMP is used as a sequestrant and has applications within a wide variety of industries, including as a food additive in which it is used under the E number E452i. Sodium carbonate is sometimes added to SHMP to raise the pH to 8.0–8.6, which produces a number of SHMP products used for water softening and detergents.

A significant use for sodium hexametaphosphate is as a deflocculant in the production of clay-based ceramic particles.[3][4][5][6] It is also used as a dispersing agent to break down clay and other soil types.[7]

It is used as an active ingredient in toothpastes as an anti-staining and tartar prevention ingredient.[8]

Food additive

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 sodium hexametaphosphate. [9][10][11]


SHMP is prepared by heating monosodium orthophosphate to generate sodium acid pyrophosphate:

2 NaH2PO4 → Na2H2P2O7 + H2O

Subsequently, the pyrophosphate is heated to give the corresponding sodium hexametaphosphate:

3 Na2H2P2O7 → (NaPO3)6 + 3 H2O

followed by rapid cooling.


SHMP hydrolyzes in aqueous solution, particularly under acidic conditions, to sodium trimetaphosphate and sodium orthophosphate.[12]


  1. ^ Merck Index, 12th Edition, Sodium polymetaphosphate, 8814
  2. ^ Van Wazer, John R. Phosphorus and its compounds. New York : Interscience Publishers (1958)
  3. ^ 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.
  4. ^ 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)
  5. ^ 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
  6. ^ 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.
  7. ^ ASTM D422 – 63(2007) Standard Test Method for Particle-Size Analysis of Soils.
  8. ^ Crest Pro-Health Frequently Asked Questions
  9. ^
  10. ^
  11. ^
  12. ^ Van Wazer, John (1958). Phosphorus and its Compounds. New York: Interscience Publishers. Retrieved 7 April 2015. 

External links

  • Occupational Health and Safety Agency for Healthcare in British Columbia
  • Use of phosphates (including sodium hexametaphosphate) in industry
  • Material Safety Data Sheet

This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from World eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.