What are polyoxometalates used for?
Polyoxometalates (POM) have been well-known as active catalysts for the oxidation of organic compounds with hydrogen peroxide in both heterogeneous and homogeneous systems [1-3].
How are polyoxometalates made?
Polyoxometalates (POMs) are combinations between oxygen and early transition metals (e.g., M = V, Nb, Ta, Mo, W) at their highest oxidation states. They may also contain a variety of heteroatoms (e.g., X = P, As, Si, Ge). POMs are molecular oxides which are distinguishable from the majority of metal oxides.
What is a Keggin ion?
Keggin structure is the best known structural form for heteropoly acids. It is the structural form of α-Keggin anions, which have a general formula of [XM12O40]n−, where X is the heteroatom (most commonly are P5+, Si4+, or B3+), M is the addendum atom (most common are molybdenum and tungsten), and O represents oxygen.
What is a Keggin unit?
2 The Keggin unit is the primary structure of the heteropoly acids and contains 12 transition metal atoms normally of tungsten or molybdenum, a central atom (usually phosphorus or silicon), and four types of oxygen atoms: central oxygens, terminal oxygens, and two types of bridging oxygens [ 3 ] Source publication.
What is Isopoly and heteropoly acids?
In other words, isopoly acids contain only one metal along with hydrogen and oxygen while heteropoly acids contain two elements other than hydrogen and oxygen. The corresponding salts of isopoly and heteropoly acids are called as isopoly and heteropoly salts, respectively.
What are Heteropolyanions?
heteropolyanion (plural heteropolyanions) (inorganic chemistry) An anion derived from a heteropoly acid.
What is heteropoly blue?
Abstract. Polyoxotungstate, -molybdate and -vanadate anions in which the metal atoms occupy sites of approximately C4V symmetry with one terminal oxygen each, are reducible in reversible one- or two-electron steps to mixed-valence polyanions (heteropoly blues).
What is Isopoly acid Example?
Isopoly acids are inorganic acidic compounds that form from the combination of acids or anions of the same type. For example, isopoly acids of molybdenum forms when molybdenum trioxide is dissolved in aqueous sodium hydroxide.
What is Isopoly and heteropoly?
What is Phosphomolybdate blue?
The heteropoly-molybdenum blues have structures based on the Keggin structure. The blue colour arises because the near-colourless anion, such as the phosphomolybdate anion, PMo. 12O 3− 40. , can accept more electrons (i.e. be reduced) to form an intensely coloured mixed-valence complex.
Is phosphate an element?
Phosphates are the naturally occurring form of the element phosphorus, found in many phosphate minerals. In mineralogy and geology, phosphate refers to a rock or ore containing phosphate ions.
What are Isopoly acids?
: any of a large group of complex oxygen-containing acids derived from a single inorganic acid by elimination of water from two or more molecules —distinguished from heteropoly acid.
Which is the best description of a polyoxometalate?
L. Cronin, in Comprehensive Inorganic Chemistry II (Second Edition), 2013 Polyoxometalates (POMs) are a class of metal oxides with discrete molecular structures of various shapes and sizes, possessing a diverse range of associated properties.
How are polyoxometalates encapsulated in a MOF pore?
In addition, polyoxometalates can be encapsulated in MOF pores by host–guest interactions to form MOF polyoxometalate composites [38,39]. Polyoxometalates (POMs) are a type of inorganic polyanionic clusters bearing well-defined topologic architecture comprised of early transition oxo-metalates.
What makes a pom different from other polyoxometalates?
POMs are sometimes viewed as soluble fragments of metal oxides. Recurring structural motifs allow POMs to be classified. Iso -polyoxometalates (isopolyanions) feature octahedral metal centers. The heteropolymetalates form distinct structures because the main group center is usually tetrahedral.
How are polyoxometalates used in flash memory devices?
Polyoxometalates have been shown to catalyse water splitting. non-volatile (permanent) storage components, also known as flash memory devices. Some POMs exhibit unusual magnetic properties and are being investigated as possible nanocomputer storage devices (see qubits ).