CaZrGeO5 and the triclinic instability of the titanite structure type
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Thomas Malcherek
Abstract
CaZrOGeO4 has been synthesized and its structure has been refined from X-ray powder diffraction data as triclinic, A1̅ (P1̅). A displacive structural phase transition to a monoclinic structure of the titanite aristotype with space group symmetry A2/a (C2/c) is observed near 488 K. The non-symmetry breaking spontaneous strain below the phase transition corresponds to a contraction of the structure normal to the octahedral chain direction. The coordination of Ca changes from 7-fold in the high temperature phase to 8-fold in the triclinic low temperature phase. A limiting monoclinic-angle is postulated below which compounds of the titanite topology and general stoichiometry CaMOXO4 distort to triclinic symmetry.
© by Oldenbourg Wissenschaftsverlag, München
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Articles in the same Issue
- Phase Transitions
- Structural phase transitions in two-dimensional systems: Pb/Ge(111) and Sn/Ge(111)
- Theoretical approach to reconstructive and morphotropic phase transitions
- Surface relaxations at mineral surfaces
- Methods for pseudosymmetry evaluation: a comparison between the atomic displacements and electron density approaches
- Revised prediction of B1 to B2 phase transition pressures in YbN, YbP and YbAs
- Crossover from classical to 3d-Ising critical behaviour near the antiferrodistortive phase transition of lawsonite
- CaZrGeO5 and the triclinic instability of the titanite structure type
- The high-pressure structural phase transitions of sodium bismuth titanate
- Ferroelastic phase transitions and domain structures in powders
- Phase transitions in BaTiO3: a high-pressure neutron diffraction study
- Nanoscale phase transformations in relaxor-ferroelectric lead scandium tantalate and lead scandium niobate
- On the nanostructure of radiation-amorphized zircon and pyrochlores: a small-angle x-ray scattering study
