Sodium aluminium phosphate

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Sodium aluminium phosphate
Other names
  • E541
  • aluminium sodium salt
Abbreviations SALP, SAlP
ECHA InfoCard 100.029.173 Edit this at Wikidata
EC Number
  • 232-090-4
E number E541 (acidity regulators, ...)
Molar mass 144.943 g/mol
Appearance white powder
Odor odorless
Solubility soluble in HCl
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Sodium aluminium phosphate (SAlP) describes the inorganic compounds consisting of sodium salts of aluminium phosphates. The most common SAlP has the formulas NaH14Al3(PO4)8·4H2O and Na3H15Al2(PO4)8.[1] These materials are prepared by combining alumina, phosphoric acid, and sodium hydroxide.[2]

In addition to the usual hydrate, an anhydrous SAlP is also known, Na3H15Al2(PO4)8 (CAS#10279-59-1), referred to as 8:2:3, reflecting the ratio of phosphate to aluminium to sodium. Additionally an SAlP of ill-defined stoichiometry is used (NaxAly(PO4)z (CAS# 7785-88-8).[3]

The acidic sodium aluminium phosphates are used as acids for baking powders for the chemical leavening of baked goods.[4] Upon heating, SAlP combines with the baking soda to give carbon dioxide. Most of its action occurs at baking temperatures, rather than when the dough or batter is mixed at room temperature. SAlPs are advantageous because they impart a neutral flavor.

As a food additive, it has the E number E541.[5][6] Basic sodium aluminium phosphates are also known, e.g., Na15Al3(PO4)8. These species are useful in cheese making.[2]


  1. ^ 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
  2. ^ a b "Phosphoric Acids and Phosphates" David R. Gard, 2005, Wiley-VCH. doi:10.1002/0471238961.1608151907011804.a01.pub2
  3. ^ Lampila, Lucina E. (2013). "Applications and functions of food-grade phosphates". Ann. N.Y. Acad. Sci. 1301 (1): 37–44. Bibcode:2013NYASA1301...37L. doi:10.1111/nyas.12230. PMID 24033359.
  4. ^ "Sodium Aluminium Phosphate (SALP) | Baking Ingredients". BAKERpedia. 7 June 2015. Retrieved 2020-04-07.
  5. ^ Brooks, David W. "Leavening Agents". Teaching and Research Web Site. University of Nebraska - Lincoln. Archived from the original on 2011-07-20. Retrieved 2011-03-06.
  6. ^ "E541 : Sodium aluminum phosphate". Food-Info. Wageningen University. Retrieved 2011-03-06.