![cover image](https://wikiwandv2-19431.kxcdn.com/_next/image?url=https://upload.wikimedia.org/wikipedia/commons/thumb/6/60/Phosphotungstate-3D-polyhedra.png/640px-Phosphotungstate-3D-polyhedra.png&w=640&q=50)
Phosphotungstic acid
Chemical compound / From Wikipedia, the free encyclopedia
Dear Wikiwand AI, let's keep it short by simply answering these key questions:
Can you list the top facts and stats about Phosphotungstate?
Summarize this article for a 10 year old
Phosphotungstic acid (PTA) or tungstophosphoric acid (TPA), is a heteropoly acid with the chemical formula H3PW12O40]. It forms hydrates H3[PW12O40]·nH2O. It is normally isolated as the n = 24 hydrate but can be desiccated to the hexahydrate (n = 6).[2] EPTA is the name of ethanolic phosphotungstic acid, its alcohol solution used in biology. It has the appearance of small, colorless-grayish or slightly yellow-green crystals, with melting point 89 °C (24 H2O hydrate). It is odorless and soluble in water (200 g/100 ml). It is not especially toxic, but is a mild acidic irritant. The compound is known by a variety of names and acronyms (see 'other names' section of infobox).
![]() | |
![]() | |
Names | |
---|---|
Other names
Tungstophosphoric acid (TPA) Phosphotungstic acid (PTA, PWA) 12-Phosphotungstic acid 12-Tungstophosphoric acid[1] Dodecatungstophosphoric acid | |
Identifiers | |
| |
3D model (JSmol) |
|
ChemSpider | |
ECHA InfoCard | 100.108.885 ![]() |
EC Number |
|
PubChem CID |
|
UNII | |
CompTox Dashboard (EPA) |
|
| |
| |
Properties | |
H3[PW12O40] | |
Molar mass | 2880.2 g/mol (anhydrous) |
Melting point | 89 °C (192 °F; 362 K) (hydrate) |
Hazards | |
GHS labelling: | |
![]() ![]() ![]() | |
Danger | |
H302, H314, H411 | |
P260, P264, P270, P273, P280, P301+P312, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P321, P330, P363, P391, P405, P501 | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|
In these names the "12" or "dodeca" reflects the fact that the anion contains 12 tungsten atoms. Some early workers who did not know the structure[3] called it phospho-24-tungstic acid, formulating it as 3H2O·P2O5 24WO3·59H2O, (P2W24O80H6)·29H2O, which correctly identifies the atomic ratios of P, W and O. This formula was still quoted in papers as late as 1970.[4]
Phosphotungstic acid is used in histology as a component for staining of cell specimens, often together with haematoxylin as PTAH. It binds to fibrin, collagen, and fibres of connective tissues, and replaces the anions of dyes from these materials, selectively decoloring them.
Phosphotungstic acid is electron dense, opaque for electrons. It is a common negative stain for viruses, nerves, polysaccharides, and other biological tissue materials for imaging by a transmission electron microscope.