Tungstophosphoric acid

Structural formula
General
Surname	Tungstophosphoric acid
other names	12-tungstophosphoric acid Phosphotungstic acid Dodecatungframophosphoric acid Trihydrogen phosphododecatungstate Scheibler's reagent Folin's reagent
Molecular formula	H 3 PW 12 O 40
Brief description	white or slightly yellowish green crystals
External identifiers / databases
CAS number 12501-23-4 (unspecific hydrate) 1343-93-7 (anhydrate) EC number 603-020-3 ECHA InfoCard 100.108.885 PubChem 71308707 Wikidata Q2246598
properties
Molar mass	2880.2 g mol −1
Physical state	firmly
Melting point	95 ° C
solubility	soluble in water, ethanol and diethyl ether
safety instructions
GHS labeling of hazardous substances danger H and P phrases H: 314 P: 280-305 + 351 + 338-310
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Tungstophosphoric acid is a phosphoric acid - tungsten compound and belongs to the heteropoly acids .

Extraction and presentation

The compound can be obtained by reacting sodium tungstate with phosphoric acid .

properties

Tungstophosphoric acid crystallizes as a hydrate with 44 molecules of water in the crystal lattice.

use

Tungstophosphoric acid is used as Scheibler's reagent for the detection of alkaloids (yellow precipitate) and as the Folin-Ciocalteu reagent for the detection of uric acid , phenol or ascorbic acid. Other areas of application include antistatic finishing in the textile industry, printing inks, paper dyes and the pigmentation of waxes. It is also used in histology to color the connective tissue.

Individual evidence

1. ↑ ^{a b c d e} Entry on 12-tungstophosphoric acid. In: Römpp Online . Georg Thieme Verlag, accessed on January 20, 2014.
2. ↑ ^{a b c} Datasheet Phosphotungstic acid hydrate from Sigma-Aldrich , accessed on January 20, 2014 ( PDF ).