Results 91 to 100 of about 549 (136)

Geochemical alteration of pyrochlore group minerals; pyrochlore subgroup

American Mineralogist, 1995
Primary alteration of uranpyrochlore from granitic pegmatites is characterized by the substitutions ADYD-+ ACaYO,ANaYF-+ ACaYO,and ANaYOI-I--+ ACaYO.Alteration occurred at "" 450-650 °C and 2-4 kbar with fluid-phase compositions characterized by relatively low aNa+,high aeaH, and high pH.
Gregory R. Lumpkin, Rodney C. Ewing
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Luminescence of Pyrochlores

Journal of Solid State Chemistry, 1994
Abstract The luminescence of the pyrochlores Y2Ti2O7, Cd2Nb2O7, and Pb2Nb2O7 is reported and discussed. Relations with the luminescence of comparable compounds is made.
M. Hamoumi, M. Wiegel, G. Blasse
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Pyrochlores. X. Madelung energies of pyrochlores and defect fluorites

Canadian Journal of Chemistry, 1976
Electrostatic (Madelung) lattice energies have been calculated for a wide range of compounds A2B2X6Y with the pyrochlore-type structure. The cases of disorder and partial disorder on the non-metal sites have been examined, as well as the inverse case, where Y is a positive ion.
William W. Barker, Peter S. White, Osvald Knop   +2 more
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Pyrochlore-type tin niobate

Acta Crystallographica Section C Crystal Structure Communications, 2001
A single crystal of Sn(1.59)Nb(1.84)O(6.35) was grown at 1273 K from a mixture of sodium niobate and tin(II) chloride. The structure is of pyrochlore type A(2)B(2)O(7). The tin is partially oxidized to tin(IV) and competes with niobium for the occupation of site B.
L P, Cruz, J M, Savariault, J, Rocha
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The new pyrochlore Gd2GaSbO7

Journal of Physics and Chemistry of Solids, 1984
Preparation du compose a partir d'un melange Ga 2 O 3 , Sb 2 O 3 et Gd 2 O 3 dans les rapports molaires 1:1:2, par chauffage a l'air a differentes temperatures.
P. Garcia Casado, I. Rasines
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Crystal Chemistry of Pyrochlore

Journal of the American Ceramic Society, 1962
Analyses of natural minerals suggest the wide variety of both cationic and anionic substitutions possible in the pyrochlore structure. Limits on the possibilities of ionic substitution in pyrochlore have been determined by the preparation of a large number of compounds.
EUGENE ALESHIN, RUSTUM ROY
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FRUSTRATION IN THE PYROCHLORE ANTIFERROMAGNETS

Modern Physics Letters B, 1996
In an antiferromagnet with the pyrochlore structure, the magnetic ions are situated on a framework of corner-sharing tetrahedra. This lattice results in a high degree of geometrical frustration, and theoretical studies predict that the magnetic ground state is continuously disordered.
M.J. HARRIS, M.P. ZINKIN
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Microstructure and Composition of a Ce-pyrochlore: A Chemical Analog for Pu-pyrochlore

AIP Conference Proceedings, 2003
Ce‐pyrochlore (CaCeTi2O7), is a chemical analogue for CaPuTi2O7, which is a proposed ceramic waste form for deposition of excess weapon‐usable Pu in geological repositories. Ce‐pyrochlore was synthesized by firing and annealing a mixture of Ce(NO3)4, TiO2, and Ca(OH)2 with a stoichiometry of CaCeTi2O7 at 1,300°C for 50 hours.
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Disorder in Pyrochlore Oxides

Journal of the American Ceramic Society, 2000
Contour plots of disorder reaction energies across a wide variety of A 2 B 2 O 7 pyrochlore oxides have been produced, using atomistic simulation calculations based on energy‐minimization techniques.
Licia Minervini, Robin W. Grimes, Kurt E. Sickafus   +2 more
exaly   +2 more sources

Nanoscale Manipulation of Pyrochlore

2001
Physical Review ...
Boatner, L. A., Chen, J., Lian, J., Wang, L. M., Wang, S. X.   +4 more
openaire   +1 more source