Borisova E. Silicates and double silicate of sodium and rare earth elements with the structure of apatite

X-ray diffraction analysis, including the Rietveld algorithm, scanning electron microscopy with energy dispersive X-ray spectrometer, infrared spektrosopy and conductivity measurements in the range of 300-700°C. The conditions of synthesis, refined crystal structure and study the properties of silicates and double REE silicates and sodium. The conditions for the solid phase synthesis of REE silicates using nano-sized silicon dioxide in the form of Oris and double silicate of sodium and REE sol-gel method using tetraethoxysilane. As a result, rare earth silicates synthesized fine a grain size of 1 micron and double silicates having grain sizes of 0.5 microns or less predetermined composition with a uniform distribution of components in the samples. Found that the substitution at La Nd, Eu, Gd, Ho in the structure of apatite-REE Lа9-хLnх(SiO4)6O(OH) occurs 1200 °C over the entire range investigated compositions from x = 0 to x = 9. Assess the stability of the continuous series of solid solutions at different temperatures. Rietveld method (no vacancy in the position of O(OH)(4)) and infrared spectroscopy (presence bands of stretching vibrations OH-groups located in the channels of the structure at 3566sm-1) shows that the apatite REE are oxyhydroxyapatite, not to hydroxyapatite, as it was supposed earlier. As a result of verifying the crystal structure of double sodium silicates, oxysulfides, and found that the lanthanide atoms are located in positions Ln(1) together with sodium atoms. In positions Ln(2) atoms are REE. The oxygen atoms O(4) occupy the center of the triangle of atoms arranged in positions Ln(2). It has been established that the conductivity of the ceramic double silicates of sodium and rare earth (Nd, Eu, Ho) in the temperature range 300-700°C the conductivity exceeds certain silicates of lanthanum, not containing sodium, although inferior conduction silicates containing excess oxygen.