This work presents the results of studying dilute aqueous solutions of commercial (NO) · HO salts with = Ce-Lu using X-ray diffraction (XRD), IR spectroscopy, X-ray absorption spectroscopy (XAS: EXAFS/XANES), and pH measurements. As a reference point, XRD and XAS measurements for characterized (NO) · HO microcrystalline powder samples were performed. The local structure of -nitrate complexes in 20 mM (NO) · HO aqueous solution was studied under total external reflection conditions and EXAFS geometry was applied to obtain high-quality EXAFS data for solutions with low concentrations of ions.
View Article and Find Full Text PDFThe crystal and local structures of Czochralski-grown calcium orthovanadate (Ca(VO)) single crystals doped with over-stoichiometric 0.05 wt % MnO (CVO:0.05Mn) and annealed under different conditions are studied by single-crystal conventional and synchrotron X-ray diffraction, X-ray absorption spectroscopy, and electron paramagnetic resonance for the first time.
View Article and Find Full Text PDFLaser Ca(VO) single crystals (СVO; space group 3, = 21) with crystallochemical formula Ca1Ca2Ca3Ca4(Ca5 + Са5А)(V1V2V3)O grown by the Czochralski method were doped with МnO (CVO:МnO) and СoO (CVO:CoO) by high-temperature diffusion annealing. Statistical and local structures were comprehensively studied by single-crystal and powder synchrotron X-ray diffraction and conventional single-crystal X-ray diffraction as well as by X-ray absorption spectroscopy for the first time. The presence of Mn ions with a mixed formal charge and Co ions in the Ca2 (monocapped trigonal prism), Ca3 (two-capped trigonal prism), and Ca4 (octahedron) sites was revealed by diffraction methods.
View Article and Find Full Text PDFTitanosilicalite of the MFI type was obtained a hydrothermal method. Its initial and annealed at 75 °C (TS-1P(75)) and 500 °C (TS-1P(500)) forms were studied by X-ray powder diffraction (PXRD), X-ray absorption spectroscopy (XAS-method), Fourier-transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), temperature-programmed ammonia desorption (TPD NH), and pyridine adsorption (Py). The full-profile Rietveld method allowed us to observe the presence of the organic template tetrapropylammonium hydroxide (TPAOH) in the framework voids, as well as to determine the silicate module (Si/Ti = 73.
View Article and Find Full Text PDFResults of a detailed structural characterization of nominally pure and doped single crystals of scheelite, eulytin, and perovskite families obtained by melt methods were considered and analyzed. The influence of growth and post-growth annealing conditions on actual compositions of crystals is shown. The reasons for the coloration of the crystals are explained.
View Article and Find Full Text PDFNanocomposites based on poly(-vinylcaprolactam) containing functional nano-anatase particles were produced by mixing and mechanical grinding of mixtures of poly(-vinylcaprolactam) and Hombifine N (nano-anatase) powders in a porcelain mortar (method 1) and by mechanical milling of the same powders using a high-energy planetary ball mill (method 2). Differences in the diffraction patterns of nanocomposites prepared by method 1 (partial crystallization and an amorphization of nano-anatase particles in the nano-anatase/poly(-vinylcaprolactam) composite) and method 2 (amorphization of nano-anatase particles) were found. An increase in the X-ray intensity was found to cause physical degradation of the polymer in nano-anatase/poly(-vinylcaprolactam) composites depending on its prehistory.
View Article and Find Full Text PDFIndividual compounds and solid solutions are obtained under hydrothermal conditions in the Bi(2)O(3)-SiO(2)-MnO(2) system in the form of faceted crystals and epitaxial films on the Bi(24)Si(2)O(40) substrate. The crystals have the shape of a cube (for the molar ratio of the starting components Na(2)SiO(3)·9H(2)O:Mn(NO(3))(2)·6H(2)O > 1), a tetrahedron (for Na(2)SiO(3)·9H(2)O:Mn(NO(3))(2)·6H(2)O < 1), or a tetrahedron-cube combination (for Na(2)SiO(3)·9H(2)O:Mn(NO(3))(2)·6H(2)O = 1). Crystal-chemical analysis based on the data of single-crystal and powder X-ray diffraction, IR spectra, and the results of calculation of the local balance by the bond-valence method reveals formation of the Bi(24)(Si(4+),Mn(4+))(2)O(40) phases, which probably include Mn(5+) ions (epitaxial films), as well as the Bi(24)(Si(4+),Bi(3+),Mn(4+))(2)O(40) and Bi(24)(Si(4+),Mn(4+))(2)O(40) phases in the (1 - x)Bi(3+)(24)Si(4+)(2)O(40) - x(Bi(3+)(24)Mn(4+)(2)O(40)) system and the Bi(24)(Bi(3+),Mn(4+))(2)O(40) phase in the (1 - x)Bi(3+)(24)Bi(3+)(2)(O(39)ⁱ(1)) - x(Bi(3+)(24)Mn(4+)(2)O(40)) system.
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