Phosphomolybdic acid is the heteropolymetalate with the formula . 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
Organic synthesis is a special branch of chemical synthesis and is concerned with the intentional construction of organic compounds. Organic molecules are often more complex than inorganic compounds, and their synthesis has developed into one o ...
.
Histology
Phosphomolybdic acid is a component of
Masson's trichrome stain.
Organic synthesis
Phosphomolybdic is used as a stain for developing
thin-layer chromatography plates, staining
phenolics,
hydrocarbon waxes,
alkaloids, and
steroid
A steroid is a biologically active organic compound with four rings arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes that alter membrane fluidity; and a ...
s.
Conjugated unsaturated compounds reduce PMA to
molybdenum blue. The color intensifies with increasing number of double bonds in the molecule being stained.
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.
See also
*
Phosphotungstic acid
*
Folin-Ciocalteu reagent
References
{{reflist
Molybdenum(VI) compounds
Inorganic phosphorus compounds
Heteropoly acids