Thorium molybdate

Thorium Molybdate, Th(Mo04)2, is obtained by fusing partly dehydrated thorium chloride with excess of anhydrous sodium molybdate. It pelds tetragonal crystals, with axial ratio... 

Fluoride, in the absence of interfering anions (including phosphate, molybdate, citrate, and tartrate) and interfering cations (including cadmium, tin, strontium, iron, and particularly zirconium, cobalt, lead, nickel, zinc, copper, and aluminium), may be determined with thorium chloranilate in aqueous 2-methoxyethanol at pH 4.5 the absorbance is measured at 540 nm or, for small concentrations 0-2.0 mg L 1 at 330 nm. 

A volumetric method is based on the fact that ammonium molybdate precipitates thorium as the normal molybdate but has no action on the rare earth elements.3 The mixed nitrates are dissolved in 1 15 acetic acid to which a little sodium acetate has been added. This solution is titrated cold with ammonium molybdate, using diphenylcarbazide as an outside indicator. The end point is the appearance of a deep rose color which fades quickly. Another volumetric method 4 precipitates thorium from a mixed nitrate solution with hot oxalic acid let stand, filter, wash, and add the precipitate to hot water, then add 1 1 sulfuric acid and titrate with decinormal permanganate. 

Anion-exchange distribution coefficients for most metallic elements in sulfuric acid solution have been measured [22, 23]. Uranium(VI), thorium(IV), molybde-num(VI) and a few other elements are retained selectively by anion-exchangers from solution in approximately 6 M nitric acid [24]. 

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