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In chemistry, a polyoxometalate (abbreviated POM) is a polyatomic ion, usually an anion, that consists of three or more transition metal oxyanions linked together by shared oxygen atoms to form closed 3-dimensional frameworks. The metal atoms are usually group 6 (Mo, W) or less commonly group 5 (V, Nb, Ta) and group 7 (Tc, Re) transition metals ...
Monocryl has a low tissue reactivity, maintains high tensile strength, and has a half-life of 7 to 14 days. At 1 week, its in vivo tensile strength is at 50–60% undyed (60–70% dyed), 20–30% undyed (30–40% dyed) at two weeks, and essentially completely hydrolyzed by 91–119 days. [ 3 ]
Metal oxide surfaces can have both Brønsted and Lewis acid sites present at the same time which leads to a nonspecific interaction between the oxide and the indicator. [16] Also, as outlined in the theory section, the perturbation of neighboring sites upon adsorption of indicator molecules compromises the integrity of this model.
A trioxide is a compound with three oxygen atoms. For metals with the M 2 O 3 formula there are several common structures. Al 2 O 3, Cr 2 O 3, Fe 2 O 3, and V 2 O 3 adopt the corundum structure.
Also acid ionization constant or acidity constant. A quantitative measure of the strength of an acid in solution expressed as an equilibrium constant for a chemical dissociation reaction in the context of acid-base reactions. It is often given as its base-10 cologarithm, p K a. acid–base extraction A chemical reaction in which chemical species are separated from other acids and bases. acid ...
The oxide ion has an ionic radius of 1.40 Å, molybdenum(VI) is much smaller, 0.59 Å. [1] There are strong similarities between the structures of the molybdates and the molybdenum oxides, ( MoO 3 , MoO 2 and the " crystallographic shear " oxides, Mo 9 O 26 and Mo 10 O 29 ) whose structures all contain close packed oxide ions.
A metal ion in aqueous solution or aqua ion is a cation, dissolved in water, of chemical formula [M(H 2 O) n] z+. The solvation number , n , determined by a variety of experimental methods is 4 for Li + and Be 2+ and 6 for most elements in periods 3 and 4 of the periodic table .
However, by removing one electron from dihelium, the stable gas-phase species He + 2 ion is formed with bond order 1/2. Another molecule that is precluded based on this principle is diberyllium. Beryllium has an electron configuration 1s 2 2s 2, so there are again two electrons in the valence level. However, the 2s can mix with the 2p orbitals ...