StructureGd3NbO7 has an orthorhombic weberite-type crystal structure and undergoes a phase transition at about 340 K. The phase transition was confirmed by second harmonic generation, heat capacity measurement, and high-resolution X-ray diffraction. Above 340 K, Gd3NbO7 has a centrosymmetric weber...
The structure type of the weberite family is named after the parent compound, the mineral Na2MgAlF7. The structure can be viewed as a four-fold superstructure of the cubic fluorite structure (CaF2). The ordering of cations and anion vacancies, as well as a shift of some of the anions, ...
Gd_3NbO_7 has an orthorhombic weberite-type crystal structure and undergoes a phase transition at about 340 K. The phase transition was confirmed by second harmonic generation, heat capacity measurement, and high-resolution X-ray diffraction. Above 340 K, Gd_3NbO_7 has a centrosymmetric weber...
Below the phase transition, the high temperature phase transforms into a weberite-type structure with space group Pmcn (No. 62). The phase transformation primarily involves the off-center shifting of Nb5+ ions inside the NbO6 octahedra, combined with shifts of one third of the Ln3+ (Ln3+...
A consideration of the structures from the viewpoint of anion-centered tetrahedral arrays shows that zirconolite can be considered as an anion-deficient fluorite derivative phase. However, the fluorite-type topology of edge-shared OM4 tetrahedra is not maintained in the Ca2Ta2O7 weberite-type ...
Phase cazrti2o7Solid-solutionMetal-oxidesCazrxti3-xo7PyrochloreTetrahedraNew weberite-type Ca2Ta2O7 and zirconolite-type CaZrTi2O7 polytypes have been prepared by doping with Nd/Zr and Th/Al, respectively, and their structures have been refined using single-crystal X-ray diffraction intensity ...
A new full color emitting single phase phosphor in Bi 3+ and Eu 3+ ion co-doped La 3 TaO 7 weberite system was developed via a conventional high temperature ceramic method. Phase, structural and luminescence characteristics of the developed phosphor were evaluated with different concentrations of...
The successful synthesis of this phase demonstrates that titanium can stabilize heretofore unknown Mg–Si-oxides, the major Earth and rocky planet-forming materials, and can provide new constraints on thermobarometry of wadsleyite/ringwoodite, and garnet-bearing assemblages....
Ca2Os2O7adopts a stoichiometric, orthorhombic weberite structure but the distortion of the OsO6octahedra and eightfold Ca鈥揙 co-ordinations decrease with increasing temperature indicating that this material lies close to the weberitepyrochlore phase boundary. The lead and thallium phases adopt oxygen ...
Above the phase transition temperature, Ln 3+ and Nb 5+ sit at a position with mirror symmetry and 2-fold axis. Below the phase transition temperature, Ln 3+ and Nb 5+ shift away from the 2-fold axis but still in the mirror plane. ► La 3NbO 7 and Nd 3NbO 7 exhibit a phase...