Buscar
Mostrando ítems 1-10 de 24
THE PYROCHLORE SUPERGROUP OF MINERALS: NOMENCLATURE
(MINERALOGICAL ASSOC CANADA, 2010)
A new scheme of nomenclature for the pyrochlore supergroup, approved by the CNMNC-IMA, is based on the ions at the A, B and Y sites. What has been referred to until now as the pyrochlore group should be referred to as the ...
Potassium disorder in the defect pyrochlore KSbTeO6: A neutron diffraction study
(MDPI AG, 2017-01-13)
KSbTeO6 defect pyrochlore has been prepared from K2C2O4, Sb2O3, and 15% excess TeO2 by solid-state reaction at 850 °C. Direct methods implemented in the software EXPO2013 allowed establishing the basic structural framework. ...
Structure-properties relationship in the hydronium-containing pyrochlores (H3O)1+: PSb1+ pTe1- pO6with catalytic activity in the fructose dehydration reaction
(Royal Society of Chemistry, 2020-07-13)
A series of defect pyrochlores of the composition (H3O)1+pSb1+pTe1−pO6 have been prepared by ion exchange from K-containing pyrochlores K1+pSb1+pTe1−pO6 in sulfuric acid at 280 °C for 24 h. The structural characterization ...
The crystal structure of defect KBB’O6 pyrochlores (B,B’: Nb,W,Sb,Te) revisited from neutron diffraction data
(MDPI AG, 2018-10-20)
Three defect pyrochlores KNbWO6·xH2O, KNbTeO6 and KSbWO6 were synthesized by solid state reaction at 750 °C, from stoichiometric mixtures of K2C2O4, Sb2O3, Nb2O5, WO3 and 20% excess TeO2. A neutron powder diffraction (NPD) ...
Structural, hyperfine and Raman properties of RE2FeSbO7compounds
(Elsevier Science Sa, 2015-01)
Pyrochlores of the RE2FeSbO7type were synthesized by ball-milling followed by annealing in free atmosphere at high temperatures. The samples prepared were characterized by X-ray diffraction, Raman spectroscopy and 57Fe ...
Intermediate magnetization state and competing orders in Dy2Ti2O7 and Ho2Ti2O7
(Nature Publishing Group, 2016-08)
Among the frustrated magnetic materials, spin-ice stands out as a particularly interesting system. Residual entropy, freezing and glassiness, Kasteleyn transitions and fractionalization of excitations in three dimensions ...
Fluorcalciomicrolite, (Ca,Na,□)2Ta2O6F, a new microlite-group mineral from Volta Grande pegmatite, Nazareno, Minas Gerais, Brazil
(Mineralogical SocietyTwickenham, 2013-10)
Fluorcalciomicrolite, (Ca,Na,□)2Ta2O6F, is a new microlite-group, pyrochlore supergroup mineral approved by the CNMNC (IMA 2012-036). It occurs as an accessory mineral in the Volta Grande pegmatite, Nazareno, Minas Gerais, ...
Hydrokenomicrolite, (□,H2O)2Ta2(O,OH)6(H2O), a new microlite-group mineral from Volta Grande pegmatite, Nazareno, Minas Gerais, Brazil
(Mineralogical Society of AmericaChantilly, 2013-02)
Hydrokenomicrolite, (□,H2O)2Ta2(O,OH)6(H2O) or ideally □2Ta2[O4(OH)2](H2O), is a new microlite-group mineral approved by the CNMNC (IMA 2011-103). It occurs as an accessory mineral in the Volta Grande pegmatite, Nazareno, ...
THE CRYSTAL STRUCTURE OF A MICROLITE-GROUP MINERAL WITH A FORMULA NEAR NaCaTa(2)O(6)F FROM THE MORRO REDONDO MINE, CORONEL MURTA, MINAS GERAIS, BRAZIL
(MINERALOGICAL ASSOC CANADA, 2011)
We present electron-microprobe and single-crystal X-ray-diffraction data for a microlite-group mineral with a formula near NaCaTa(2)O(6)F from the Morro Redondo mine, Coronel Murta, Minas Gerais, Brazil. On the basis of ...