Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Chemical compound
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).
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.
^Cotton FA, Wilkinson G (1966). Advanced inorganic chemistry: a comprehensive text (2nd ed.). New York: Wiley. ISBN 0470175583. LCCN 66020662. OCLC 85904497.
^Cite error: The named reference Dias was invoked but never defined (see the help page).
^Hsein W (1920). "Contribution to the chemistry of phosphomolybdic acids, phosphotungstic acids and allied substances". Journal of Biological Chemistry. 43: 189–220. doi:10.1016/S0021-9258(18)86325-6.
^Quintarelli G, Zito R, Cifonelli JA (November 1971). "On phosphotungstic acid staining. I". The Journal of Histochemistry and Cytochemistry. 19 (11): 641–7. doi:10.1177/19.11.641. PMID 4107745.
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Phosphotungsticacid (PTA) or tungstophosphoric acid (TPA), is a heteropoly acid with the chemical formula H3PW12O40]. It forms hydrates H3[PW12O40]·nH2O...
microscopy. Electron-dense compounds of heavy metals are typically used. Phosphotungsticacid is a common negative stain for viruses, nerves, polysaccharides,...
small amount of phosphotungsticacid. In the OG-6, the OG signifies Orange G and the '6' denotes the concentration of phosphotungsticacid added; other variants...
protein assay and EPTA, ethanolic phosphotungsticacid. Phosphomolybdic acidPhosphotungsticacid Silicotungstic acid Greenwood, N. N.; Earnshaw, A. (1997)...
conflicting charges. Examples of acid dyes used in medicine include: Lee's stain (stains reddish-pink). PhosphotungsticAcid Hematoxylin (PTAH) stain (stains...
peptide bonds, with Folin–Ciocalteu reagent (a mixture of phosphotungsticacid and phosphomolybdic acid in the Folin–Ciocalteu reaction). The reaction mechanism...
needed] In general α-Keggin anions are synthesized in acidic solutions. For example, 12-phosphotungsticacid is formed by condensing phosphate ion with tungstate...
hydrogens in metatungstate produces a wide variety of heteropoly acids, such as phosphotungsticacid H3PW12O40. Tungsten trioxide can form intercalation compounds...
endoplasmic reticulum, ribosomes, collagen, myelin, elastic fibers, and acid mucins. Haematoxylin alone is not an effective stain, but when oxidized to...
forms heteropoly acids and polyoxometalate ions with tungsten, molybdenum and some other transition metals, such as phosphotungsticacid (H 3PW 12O 40)...
applications. Co(H2NCH2CH2NH2)2PO4 [Pt2(HPO4)4(SC4H8)2]2− [Re3Cl9(PO4)]3− Phosphotungsticacid H3PW12O40. Bidentate, chelating: One example is [Co(ethylenediamine)2)(PO4)]...
Parliamentary Technology Assessment European Pulsar Timing Array Phosphotungsticacid Expanded Programme of Technical Assistance, a United Nations aid...
Silicotungstic acid or tungstosilicic acid is a heteropoly acid with the chemical formula H4[SiW12O40]. It forms hydrates H4[SiW12O40]·nH2O. In freshly...
Other common staining methods include the periodic acid-Schiff, Oil Red O, phosphotungsticacid, and Holmes silver nitrate method. Bielschowsky stain...
solution such as ammonium molybdate, uranyl acetate (or formate), or phosphotungsticacid.[citation needed] This mixture is applied to an EM grid, pre-coated...
298: 9. Keggin, J. F. (1934). "The Structure and Formula of 12-PhosphotungsticAcid". Proc. R. Soc. A. 144 (851): 75–100. Bibcode:1934RSPSA.144...75K...
viruses: the first was a modified negative staining method using phosphotungsticacid, and the next was immunological procedure in which she reacted viruses...
Skyscan 1172. Aluminum filters were used to optimize image quality and phosphotungsticacid (PTA) was used to enhance soft tissue extract in the embryos. Markers...
allergy skin tests, and is equivalent to 0.01 microgram (μg) of phosphotungsticacid-precipitable protein nitrogen. Potency measurements depend on the...
dispersions of total lipid extract of spinach thylakoid membranes, studied by negative staining (2% phosphotungsticacid) transmission electron microscopy....
stained with other reagents such as the Masson's trichrome stain, phosphotungsticacid-haematoxylin stain, elastic Van Gieson's stain, or Lendrum's phloxine-tartrazine...
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