Selenate salts

Selenium trioxide melts at (392.5 1 1.5) K, [62JER/MEN], [63MIJ/GER], to a colourless liquid. The decomposition of SeO ,(l) on heating was studied by Jerschkewitz and Menning [62JER/MEN] and found to be dependent on the purity of the specimen. The presence of a selenate salt, selenium dioxide, or water greatly enhances the rate of the decomposition reaction ... 

The forms of selenium expected to be found in surface water and the water contained in soils are the salts of selenic and selenious acids. Selenic acid (H2Se04) is a strong acid. The soluble selenate salts of this acid are expected to occur in alkaline waters. Sodium selenate is one of the most mobile selenium compounds in the environment because of its high solubility and inability to adsorb onto soil particles (NAS 1976a). Selenious acid (H2Se03) is a weak acid, and the diselenite ion predominates in waters between pH 3.5 and 9. Most selenites are less soluble in water than the corresponding selenates (NAS 1980b). 

Fourier transform infrared spectra of Csl pellets of the AI13- and GaAli2-sulfate and selenate salts and of the deuterated Al -sulfate salt were run on a Mattson Galaxy 4030 spectrometer at a resolution of 2 wavenumbers. 

Powder X-Ray Diffraction Studies of the Polyoxocation Selenate Salts... 

Amongst crystalline hydrogen phosphate structures, the H-bond systems often include continuous chains running through successive unit cells. This occurs in Na HPjOio, for example, [33] in which the O-H-0 distance is short (and perhaps symmetrical) (13.36c). Short H bonds (-2.47 A) of type P-O-H-O-Se have been found amongst crystalline phosphate/selenate salts [9]. 

The transargononic compounds of selenium closely resemble those of sulfur. The selenates, salts of selenic acid, H2Se04, are much like the sulfates. Telluric acid, however, has the formula Te(OH)s, in which the large central atom has increased its ligancy from 4 to 6, as the iodine atom does in HsIOe. 

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