Abstract
The solid solubility of CaTiOGeO4 with CaZrOGeO4 and the structural phase transitions occurring in this solid solution as a function of temperature and composition were examined using in situ high temperature X-ray powder diffraction. Structural phase transitions were identified based on the determination of spontaneous strain. The transition P21/a-A2/a, which is typical for titanite and CaTiOGeO4, was observed in samples with Zr concentrations up to 10%. The addition of Zr destabilizes the ordered P21/a phase and Tc decreases accordingly. The aristotype structure of titanite in space group symmetry A2/a was observed for intermediate compounds. Compounds with high Zr contents exhibit a triclinically distorted titanite structure. Their structure was modeled in space group A1̄. The triclinic structure appears at Zr contents of about 70% with Tc close to ambient temperature. Further increase of the Zr content stabilizes the triclinic structure and leads to an increase of Tc up to Tc = 488 K in CaZrOGeO4.
© 2015 by Walter de Gruyter Berlin/Boston
Artikel in diesem Heft
- Analytical perils (and progress) in electron microprobe trace element analysis applied to geochronology: Background acquisition, interferences, and beam irradiation effects
- Contributions to precision and accuracy of monazite microprobe ages
- Electron-microprobe age mapping of monazite
- Isotopic age constraints from electron microprobe U-Th-Pb dates, using a three-dimensional concordia diagram
- Monazite ages in the Chesham Pond Nappe, SW New Hampshire, U.S.A.: Implications for assembly of central New England thrust sheets
- Electron-microprobe dating as a tool for determining the closure of Th-U-Pb systems in migmatitic monazites
- Comparative isotopic and chemical geochronometry of monazite, with implications for U-Th-Pb dating by electron microprobe: An example from metamorphic rocks of the eastern Wyoming Craton (U.S.A.)
- Re-examination of the hydrogarnet structure at high pressure using neutron powder diffraction and infrared spectroscopy
- Anomalous elastic behavior and high-pressure structural evolution of zeolite levyne
- Crystal chemistry of the hydrothermally synthesized Na2(Mn1-xFex 2+)2Fe3+(PO4)3 alluaudite-type solid solution
- Thermodynamic properties of uvarovite garnet (Ca3Cr2Si3O12)
- Post-aragonite phase transformation in CaCO3 at 40 GPa
- Direct formation of the γ-CaSO4 phase in dehydration process of gypsum: In situ FTIR study
- The order-disorder character of FeOHSO4 obtained from the thermal decomposition of metahohmannite, Fe3+2(H2O)4[O(SO4)2]
- Temperature and composition dependence of structural phase transitions in Ca(TixZr1-x)OGeO4
- Low-T neutron powder-diffraction and synchrotron-radiation IR study of synthetic amphibole Na(NaMg)Mg5Si8O22(OH)2
- Charge contrast imaging of fine-scale microstructure and compositional variation in garnet using the environmental scanning electron microscope
- Piston-cylinder experiments on H2O undersaturated Fe-bearing systems: An experimental setup approaching fO₂ conditions of natural calc-alkaline magmas
- Environmentally important, poorly crystalline Fe/Mn hydrous oxides: Ferrihydrite and a possibly new vernadite-like mineral from the Clark Fork River Superfund Complex
- The true structure of wonesite, an interlayer-deficient trioctahedral sodium mica
- Clinoholmquistite discredited: The new amphibole end-member fluoro-sodic-pedrizite
- XRMapAnal: A program for analysis of quantitative X-ray maps
- Letter. Growth zoning and strain patterns inside diamond crystals as revealed by Raman maps
- Letter. Differentiation of commercial vermiculite based on statistical analysis of bulk chemical data: Fingerprinting vermiculite from Libby, Montana U.S.A.
- Letter. Crystal structure of single-crystal CaGeO3 tetragonal garnet synthesized at 3 GPa and 1000 °C
- Letter. Iron isotope exchange kinetics at the nanoparticulate ferrihydrite surface
- Letter. Cation distribution in MgFe2O4 vs. pressure and temperature: Experiments in a piston-cylinder apparatus
Artikel in diesem Heft
- Analytical perils (and progress) in electron microprobe trace element analysis applied to geochronology: Background acquisition, interferences, and beam irradiation effects
- Contributions to precision and accuracy of monazite microprobe ages
- Electron-microprobe age mapping of monazite
- Isotopic age constraints from electron microprobe U-Th-Pb dates, using a three-dimensional concordia diagram
- Monazite ages in the Chesham Pond Nappe, SW New Hampshire, U.S.A.: Implications for assembly of central New England thrust sheets
- Electron-microprobe dating as a tool for determining the closure of Th-U-Pb systems in migmatitic monazites
- Comparative isotopic and chemical geochronometry of monazite, with implications for U-Th-Pb dating by electron microprobe: An example from metamorphic rocks of the eastern Wyoming Craton (U.S.A.)
- Re-examination of the hydrogarnet structure at high pressure using neutron powder diffraction and infrared spectroscopy
- Anomalous elastic behavior and high-pressure structural evolution of zeolite levyne
- Crystal chemistry of the hydrothermally synthesized Na2(Mn1-xFex 2+)2Fe3+(PO4)3 alluaudite-type solid solution
- Thermodynamic properties of uvarovite garnet (Ca3Cr2Si3O12)
- Post-aragonite phase transformation in CaCO3 at 40 GPa
- Direct formation of the γ-CaSO4 phase in dehydration process of gypsum: In situ FTIR study
- The order-disorder character of FeOHSO4 obtained from the thermal decomposition of metahohmannite, Fe3+2(H2O)4[O(SO4)2]
- Temperature and composition dependence of structural phase transitions in Ca(TixZr1-x)OGeO4
- Low-T neutron powder-diffraction and synchrotron-radiation IR study of synthetic amphibole Na(NaMg)Mg5Si8O22(OH)2
- Charge contrast imaging of fine-scale microstructure and compositional variation in garnet using the environmental scanning electron microscope
- Piston-cylinder experiments on H2O undersaturated Fe-bearing systems: An experimental setup approaching fO₂ conditions of natural calc-alkaline magmas
- Environmentally important, poorly crystalline Fe/Mn hydrous oxides: Ferrihydrite and a possibly new vernadite-like mineral from the Clark Fork River Superfund Complex
- The true structure of wonesite, an interlayer-deficient trioctahedral sodium mica
- Clinoholmquistite discredited: The new amphibole end-member fluoro-sodic-pedrizite
- XRMapAnal: A program for analysis of quantitative X-ray maps
- Letter. Growth zoning and strain patterns inside diamond crystals as revealed by Raman maps
- Letter. Differentiation of commercial vermiculite based on statistical analysis of bulk chemical data: Fingerprinting vermiculite from Libby, Montana U.S.A.
- Letter. Crystal structure of single-crystal CaGeO3 tetragonal garnet synthesized at 3 GPa and 1000 °C
- Letter. Iron isotope exchange kinetics at the nanoparticulate ferrihydrite surface
- Letter. Cation distribution in MgFe2O4 vs. pressure and temperature: Experiments in a piston-cylinder apparatus