X-Ray Fluorescent Spectrometric Determination of Yttrium in Rare Earth Mixtures

Abstract

The great similarity in the chemical properties of Y and the rare earth group of elements prevents use of classical chemical methods for the separation and determination of Y. An x-ray fluorescent spectrometric method for determining Y in mixtures of rare earths and Th is described. for the determination of Y in ores, a preliminary rare earth group separation is required. Samples are analyzed in solution form, with Sr added as an intennal standard. At 50% Y₂O₃ content, a coefficient of variation of 0.74 is obtained for the intensity ratio. Analytical results on a series of samples agree on the average within plus or minus 2.8% of the amount found by optical emission spectrographic procedures. (auth) LaRhO₃ containing rhodium in the trivalent state has been prepared and studied by x-ray diffraction powder methods. Calculations based on the x-ray data show that LaRhC₃ has a distorted perovskite structure. It is orthorhombic, its space group is D2h(16)Pbnm and there are four formula weights per unit cell. The lattice constants are a = 5.524 A., b = 5.679 A., c = 7.900 A LaCoC₃ belongs to space group D3d (5)3m with two formula weights per unit cell. The dimensions of the rhombohedral pseudocellmore » are a = 7.64 A., alpha = 90 deg 42'. The dimensions of the primitive rhombohedral pseudo cell are ap = 6.436 A., alpha p = 60'48'. The hexagonal form of this cell has the following dimensions: a = 5.424 A., c = 13.068 A. (auth)« less