Aluminium dihydrogenphosphate

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Aluminium dihydrogenphosphate
3D model (JSmol)
EC Number
  • 236-875-2
  • InChI=1S/Al.3H3O4P/c;3*1-5(2,3)4/h;3*(H3,1,2,3,4)/q+3;;;/p-3
  • OP(=O)(O)[O-].OP(=O)(O)[O-].OP(=O)(O)[O-].[Al+3]
Molar mass 317.939 g·mol−1
Appearance white solid
Density 2.37 g/cm3
GHS labelling:
GHS05: Corrosive[1]
P280, P305+P351+P338, P310
Safety data sheet (SDS) External SDS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Aluminium dihydrogenphosphate describes inorganic compounds with the formula Al(H2PO4)3.xH2O where x = 0 or 3. They are white solids. Upon heating these materials convert sequentially to a family of related polyphosphate salts including aluminum triphosphate (AlH2P3O10.2H2O), aluminium hexametaphosphate (Al2P6O18), and aluminium tetrametaphosphate (Al4(P4O12)3). Some of these materials are used for fireproofing and as ingredients in specialized glasses.[2]

According to analysis by X-ray crystallography, the structure consists of a coordination polymer featuring octahedral Al3+ centers bridged by tetrahedral dihydrogen phosphate ligands. The dihydrogen phosphate ligands are bound to Al3+ as monodentate ligands.[3]


  1. ^ "Aluminum Phosphate Monobasic". American Elements. Retrieved January 21, 2019.
  2. ^ Klaus Schrödter; Gerhard Bettermann; Thomas Staffel; Friedrich Wahl; Thomas Klein; Thomas Hofmann (2008). "Phosphoric Acid and Phosphates". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a19_465.pub3. ISBN 978-3527306732.
  3. ^ Brodalla, D.; Kniep, R.; Mootz, D. (1981). "Eine neue Form von Al(H2PO4)3 mit dreidimensionaler Al-O-P Vernetzung" [A new form of Al(H2PO4)3 with three-dimensional Al-O-P crosslinking]. Zeitschrift für Naturforschung B. 36: 907–909. doi:10.1515/znb-1981-0803.