Ammonium phosphomolybdate

Ammonium phosphomolybdate is the inorganic salt of phosphomolybdic acid with the chemical formula (NH₄)₃PMo₁₂O₄₀. The salt contains the phosphomolybdate anion, a well known heteropolymetalate of the Keggin structural class.

Ammonium phosphomolybdate^[1]

Names
Other names Ammonium molybdophosphate Triammonium 12-molybdophosphate
Identifiers
CAS Number	12026-66-3 N 54723-94-3 (hydrate)
3D model (JSmol)	Interactive image
ChemSpider	21241450 Y
ECHA InfoCard	100.031.545
EC Number	234-714-0
PubChem CID	90479084
UNII	F7YCY6MSAO
InChI InChI=1S/12Mo.3H3N.H3O4P.36O/c;;;;;;;;;;;;;;;1-5(2,3)4;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;/h;;;;;;;;;;;;3*1H3;(H3,1,2,3,4);;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; Y Key: RIAJLMJRHLGNMZ-UHFFFAOYSA-N Y
SMILES [NH4+].[NH4+].[NH4+].[O-]P(=O)([O-])[O-].O=[Mo](=O)=O.O=[Mo](=O)=O.O=[MO](=O)=O.O=[Mo](=O)=O.O=[Mo](=O)=O.O=[Mo](=O)=O.O=[Mo](=O)=O.O=[Mo](=O)=O.O=[Mo](=O)=O.O=[Mo](=O)=O.O=[Mo](=O)=O.O=[Mo](=O)=O
Properties
Chemical formula	(NH4)3PMo12O40
Molar mass	1876.35 g/mol
Appearance	Yellow crystals
Melting point	Decomposes
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H315, H319, H335[2]
Precautionary statements	P261, P305+P351+P338[2]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

The phosphomolybdate ion, [PMo₁₂O₄₀]³⁻.

Synthesis

Ammonium phosphomolybdate can be made by heating ammonium orthomolybdate combined with phosphoric acid and nitric acid, yielding ammonium nitrate, water, and a yellow precipitate of ammonium phosphomolybdate is obtained.^[3]

12 (NH₄)₆Mo₇O₂₄(H₂O)₄ + 7 Na₂HPO₄(H₂O) + 65 HNO₃ → 7 (NH₄)₃Mo₁₂PO₄₀ + 51 NH₄NO₃ + 14 NaNO₃ + 91 H₂O

Normally, it often exists as a hexahydrate, a dark yellow fine crystal which is poorly soluble in water.^[3]

It is also obtained as a test result for phosphate ions.