Phosphomolybdic acid

Phosphomolybdic acid is the heteropolymetalate with the formula H₃[Mo₁₂PO₄₀]·12H₂O. It is a yellow solid, although even slightly impure samples have a greenish coloration. It is also known as dodeca molybdophosphoric acid or PMA, is a yellow-green chemical compound that is freely soluble in water and polar organic solvents such as ethanol. It is used as a stain in histology and in organic synthesis.^[2]

Phosphomolybdic acid

Names
Other names Molybdophosphoric acid; dodecamolybdophosphoric acid
Identifiers
CAS Number	12026-57-2 (anhydrous) Y 51429-74-4 (hydrate) Y
3D model (JSmol)	Interactive image Interactive image
ChemSpider	9426978
ECHA InfoCard	100.031.544
EC Number	234-713-5
MeSH	Phosphomolybdic+acid
PubChem CID	11251951
UNII	RN225F04V1
InChI InChI=1S/12Mo.H3O4P.36O/c;;;;;;;;;;;;1-5(2,3)4;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;/h;;;;;;;;;;;;(H3,1,2,3,4);;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; Key: DHRLEVQXOMLTIM-UHFFFAOYSA-N
SMILES OP(=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 [Mo]18%21%24(O[Mo]%16%18%23(O[Mo]56(O1)(O[Mo]247(O[Mo]9%22(O[Mo]%12%13(O2)(O[Mo]3%11%14(O[Mo]%17%19(O[Mo](O3)(O4)(O5)([O++]67[P+]%15%20[O++]89[Mo]%10(O[Mo](O[Mo](O%10)(O%11)(O%12)([O++]%13%14%15)[O-])(O%16)(O%17)([O++]%18%19%20)[O-])(O%21)(O%22)[O-])[O-])(O%23)[O-])[O-])O)(O%24)[O-])[O-])O)[O-])O
Properties
Chemical formula	H3[PMo12O40]
Molar mass	1825.25 g/mol
Density	1.62 g/ml[1] (hydrate)
Melting point	79-90 °C[1]
Solubility in water	soluble
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	Oxidiser[1] (hydrate)
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

Histology

Phosphomolybdic acid is a component of Masson's trichrome stain.^[3]

Organic synthesis

Phosphomolybdic is used as a stain for developing thin-layer chromatography plates,^[4] staining phenolics, hydrocarbon waxes, alkaloids, and steroids. Conjugated unsaturated compounds reduce PMA to molybdenum blue. The color intensifies with increasing number of double bonds in the molecule being stained.^[5]

Phosphomolybdic acid is also occasionally used in acid-catalyzed reactions in organic synthesis. It has been shown to be a good catalyst for the Skraup reaction for the synthesis of substituted quinolines.^[6]

Bismuth phosphomolybdate catalyzes ammoxidation in the Sohio process.^[7]

See also

• Phosphotungstic acid
• Folin-Ciocalteu reagent