Topic
Phosphotungstic acid
About: Phosphotungstic acid is a research topic. Over the lifetime, 1925 publications have been published within this topic receiving 38059 citations. The topic is also known as: Phosphowolframic acid.
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TL;DR: A simple technique has been developed for the study of the external form and structure of virus particles by mixing virus preparations with 1% phosphotungstic acid adjusted to pH 7.5 and spraying directly onto electron microscope supporting films made from evaporated carbon.
1,389 citations
TL;DR: In this paper, the conductivity of polybenzimidazole (PBI) and PBI composite membranes has been investigated and the results show that the conductivities of PBI and PWA composite membranes are dependent on acid doping level, relative humidity (RH) and temperature.
519 citations
TL;DR: The structure and formulae of the 12-phosphotungstic acid have been a subject for speculation as discussed by the authors, and Pauling proposed a structure for the molecules of 12-heteropoly acids, which gave the formula of 12phosphotonemic acid as H3[PO4.W12O18(OH)36]nH2O.
Abstract: THE structures and formulae of the heteropoly acids have long been a subject for speculation. In 1929, Pauling1, on theoretical grounds, proposed a structure for the molecules of the 12-heteropoly acids, which gave the formula of 12-phosphotungstic acid as H3[PO4.W12O18(OH)36]nH2O.
501 citations
TL;DR: In this article, it was shown that one atom of such elements as P, Si, As, B, Al, etc., is combined with a number of atoms of an element such as W or Mo, together with a relatively large number of oxygen.
Abstract: This acid belongs to a large class of compounds known as the heteropolyacids, of which the structures and exact formulae have long been a subject for speculation. The heteropolyacids are compounds in which one atom of such elements as P, Si, As, B, Al, etc., is combined with a number of atoms of an element such as W or Mo, together with a relatively large number of atoms of oxygen. In addition to the elements mentioned, it has been shown that the oxides of a considerable number of other elements show a tendency to form heteropolyacids. All formulae proposed indicate a relatively large number of atoms in the molecule, and a complex structure. In spite of the complexity of the molecule, many of these acids are quite stable, and form stable salts with practically all metals, The best known compounds of this group are the silicotungstic, silicomolybdic, phosphotungstic and phosphomolybdic acids, in which one atom of silicon or phosphorus is combined with a number of atoms of tungsten or molybdenum. Mixed acids are also known in which a number of tungsten atoms are replaced by molybdenum atoms, or vice versa . The heteropolyacids are classified according to the ratio of the numbers of the two types of cations present. Throughout the whole class of heteropolyacids, those acids which have the same cation-cation ratio tend to be isomorphous and have similar properties.
487 citations
TL;DR: This chapter describes a method using the preparation of plasma membranes from light-grown oat leaves as an example, and estimates the purity to be higher than 90% and often close to 100%, plasma membrane and similar purities are reported for plasma membrane from maize roots.
Abstract: Publisher Summary This chapter describes a method using the preparation of plasma membranes from light-grown oat ( Arena sativa L. ) leaves as an example. Using the batch procedure, two fractions containing purified plasma membrane (U 3 and U 3 , ) and one fraction containing intracellular membranes depleted of plasma membrane (L 1 ) are obtained. Specific staining with phosphotungstic acid or silicotungstic acid seems to be the only universal marker for the plant plasma membrane and the only one that permits a real estimation of the purity of the preparations. Based on this staining the purity is estimated to be higher than 90% and often close to 100%, plasma membrane and similar purities are reported for plasma membrane from maize roots. (>90%) for plasma membrane preparations obtained both by phase partitioning and free flow electrophoresis.
406 citations