Results 121 to 130 of about 276 (171)

Orientation disorder in ammonium elpasolites

Journal of Fluorine Chemistry, 2003
Abstract Crystal structures of the known (NH4)3AlF6(I) and (NH4)3FeF6(III) and new (NH4)3TiOF5(II) elpasolites were refined by localizing anions (F−, O2−) in four acceptable positions of the cubic system Fm3m (Z=4) with a=8.9401(3), 9.1104(3), 9.110(1) A, respectively. According to the refinement data and a rather large entropy change due to fluorine
A.A Udovenko, N.M Laptash, I.G Maslennikova   +2 more
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Prediction of new halo-elpasolites

Russian Journal of Inorganic Chemistry, 2016
We predicted elpasolites having the composition A2BCHal6 (A and C stand for different monovalent metals; B stands for trivalent metals; and Hal for F, Cl, or Br) that have not been obtained yet. Prediction was based on the data on properties of elements and simple halides only.
N. N. Kiselyova, A. V. Stolyarenko, V. V. Ryazanov, O. V. Sen’ko, A. A. Dokukin   +4 more
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Ferroelastic phase transitions in elpasolites

Ferroelectrics, 1985
The crystallography analysis of the rotation distortions in elpasolite type crystals1 showed that the structure has instability of high symmetry cubic phase (Go=O5h) in respect to rotations of the octahedra. The superposition of the two rotation types leads to different distorted phases.
I. N. Flerov, A. F. Bovina, V. N. Voronov, M. V. Gorev, S. V. Misjul, S. V. Melnikova, L. A. Shabanova   +6 more
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Entropy and the mechanism of phase transitions in elpasolites

Physics of the Solid State, 2001
The phase transitions in series of crystals with the general formulas A2BB’X6 (X=F, Cl, Br, or CN) and Pb2BB’O6 that belong to the elpasolite family (space group $$Fm\bar 3m$$ ) are analyzed.
I. N. Flerov, M. V. Gorev
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Development of an elpasolite planetary science instrument

2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD), 2016
Planetary gamma-ray and neutron spectroscopy from orbiting spacecraft has become a standard technique to measure distinctive composition and abundance signatures for key elements relevant to planetary structure and evolution. Previous instrumentation that has led to the discovery of the concentration of many elements including hydrogen (a strong ...
Suzanne F. Nowicki, Laura C. Stonehill, Daniel D. S. Coupland, Katherine E. Mesick   +3 more
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Cooperative processes in Cs2NaYbF6 elpasolite crystals

Journal of Luminescence, 2014
Abstract Spectroscopic and luminescent properties of Yb3+-doped Cs2NaYF6 and stoichiometric Cs2NaYbF6 crystals are studied in the infrared and visible spectral regions. The stoichiometric Cs2NaYbF6 compound demonstrates a visible emission when excited by the laser radiation with the wavelength of about 1 μm.
D.S. Pytalev, A. Jaffres, P. Aschehoug, P.A. Ryabochkina, A.V. Malov, N.M. Khaidukov, M.N. Popova   +6 more
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Thermodynamic properties of (NH4)2KGaF6 elpasolite

Physics of the Solid State, 2001
The heat capacity of (NH4)2KGaF6 elpasolite is measured in the temperature range from 80 to 350 K. A sequence of three phase transitions at T 1=288.5 K, T 2=250 K, and T 3=244.5 K is revealed, and the thermodynamic characteristics of these transitions are determined.
I. N. Flerov, M. V. Gorev, M. L. Afanas’ev, T. V. Ushakova   +3 more
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Crystal structure of Rb-elpasolite Rb2NaAlF6

Crystallography Reports, 2013
Single crystals of Rb2NaAlF6, the Rb analogue of the mineral elpasolite, are obtained in the NaF-Rb2CO3-Al2O3-Rb3PO4-H2O system under hydrothermal conditions, and their structure is determined by X-ray diffraction (R = 0.0188): a = 8.3087(1) A, space group \(Fm\bar 3m\), Z = 4, and ρcalcd = 3.88 g/cm3. The hypothesis that Rb elpasolite exists in nature
O. V. Yakubovich, G. V. Kiryukhina, O. V. Dimitrova   +2 more
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The Synthesis and Structures of Elpasolite Halide Scintillators

MRS Proceedings, 2009
AbstractLow-cost, high-performance gamma-ray spectrometers are urgently needed for nonproliferation and homeland security applications. Available scintillation materials fall short of the requirements for energy resolution and sensitivity at room temperature.
Pin Yang, F. Patrick Doty, Mark A. Rodriguez, Margaret R. Sanchez, Xiaowong Zhou, Kanai S. Shah   +5 more
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Thermochemical investigations on chloro-elpasolites of lanthanum

Thermochimica Acta, 1994
Abstract Elpasolites A2BLaCl6 with alkali metal chlorides (LiCl excepted) have been prepared from the melts. They are Cs2RbLaCl6 (dimorphous), Cs2KLaCl6 (trimorphous), Cs2NaLaCl6 and Rb2KLaCl6 which is stable only at T⩾748 K. According to X-ray diffraction measurements of crystal powders all compounds have modifications with the cubic elpasolite ...
G. Friedrich, H. Fink, H.J. Seifert
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