Abstract
Compression mechanisms of A2+B4+O3 ilmenites with compositions MgSiO3 (stable at high pressures), MgGeO3 (stable at moderate pressures), and MgTiO3 (stable at ambient pressure) were investigated at high pressure by single-crystal structure analysis, using both synchrotron radiation and an MoKα rotating-anode X-ray generator. The distortions of AO6 (A:Mg) and BO6 (B: Si,Ge,Ti) octahedra under pressure were parameterized by bond length, shared-face area, site-volume ratio, and A2+-B4+ interatomic distance across the shared edges and shared face. The AO6 octahedral volume is much more compressive than the BO6 octahedral volume. Of the three samples, both the AO6 and BO6 octahedra are most rigid in MgSiO3. The A2+-B4+ interatomic distance becomes more shortened with increasing pressure than do the A2+-A2+ and B4+-B4+ distances. The compression of Mg-Si is more remarkable than that of Mg-Ge and Mg-Ti. The A-B interatomic distance along c is more compressed with increasing pressure than A-A and B-B along a. The short A-B distance across the shared face becomes more shortened than the A-A and B-B distances across the shared edge. The cation position moves in the direction of c with pressure and tends to approach the center of the AO6 and BO3 octahedra with increasing pressure. The regularity of the octahedra is enhanced at higher pressure. Both quadratic elongation and bond angle variance verify the reduction of the deformation of AO6 and BO6 octahedra with pressure
© 2015 by Walter de Gruyter Berlin/Boston
Articles in the same Issue
- Crystal-size and shape distributions of magnetite from uncultured magnetotactic bacteria as a potential biomarker
- Tourmaline-bearing rocks in the Singhbhum shear zone, eastern India: Evidence of boron infiltration during regional metamorphism
- High-resolution transmission electron microscopy (HRTEM) study of the 4a and 6a superstructure of bornite Cu5FeS4
- Possible Fe/Cu ordering schemes in the 2a superstructure of bornite (Cu5FeS4)
- TEM-specimen preparation of cell/mineral interfaces by Focused Ion Beam milling
- Direct observation of spinodal decomposition in the magnetite-hercynite system by susceptibility measurements and transmission electron microscopy
- Thermodynamics of uranyl minerals: Enthalpies of formation of rutherfordine, UO2CO3, andersonite, Na2CaUO2(CO3)3(H2O)5, and grimselite, K3NaUO2(CO3)3H2O
- Mixing and ordering behavior in manganocolumbite-ferrocolumbite solid solution: A single-crystal X-ray diffraction study
- Structure change of MgSiO3, MgGeO3, and MgTiO3 ilmenites under compression
- Dehydration processes in the meta-autunite group minerals meta-autunite, metasaléeite, and metatorbernite
- Investigation of the martensitic-like transformation from Mg2GeO4 olivine to its spinel structure polymorph
- A high-temperature diffraction study of the solid solution CaTiOSiO4-CaTiOGeO4
- The vibrational spectrum of synthetic hydrogrossular (katoite) Ca3Al2(O4H4)3: A low-temperature IR and Raman spectroscopic study
- Structural characterization of biogenic Mn oxides produced in seawater by the marine bacillus sp. strain SG-1
- Investigation of smectite hydration properties by modeling experimental X-ray diffraction patterns: Part I. Montmorillonite hydration properties
- Synthesis and crystal-chemistry of alkali amphiboles in the system Na2O-MgO-FeO-Fe2O3- SiO2-H2O as a function of fO2
- Compositional zoning in sphalerite crystals
- Structure and the extent of disorder in quaternary (Ca-Mg and Ca-Na) aluminosilicate glasses and melts
- Makarochkinite, Ca2Fe42+Fe3+TiSi4BeAlO20, a new beryllosilicate member of the aenigmatite-sapphirine-surinamite group from the Ilʼmen Mountains (southern Urals), Russia
- Formation of lava stalactites in the master tube of the 1792-1793 flow field, Mt. Etna (Italy)
- Crystal-size distributions of garnets in metapelites from the northeastern Bushveld contact aureole, South Africa
- Early diagenetic origin of Al phosphate-sulfate minerals (woodhouseite and crandallite series) in terrestrial sandstones, Nova Scotia, Canada
- Scandium silicates from the Baveno and Cuasso al Monte NYF-granites, Southern Alps (Italy): Mineralogy and genetic inferences
- Letter. The effect of Fictive temperature on Al coordination in high-pressure (10 GPa) sodium aluminosilicate glasses
- Letter. α-PbO2-type nanophase of TiO2 from coesite-bearing eclogite in the Dabie Mountains, China
- Letter. Morphological characteristics of ordered kaolinite: Investigation using electron back-scattered diffraction
Articles in the same Issue
- Crystal-size and shape distributions of magnetite from uncultured magnetotactic bacteria as a potential biomarker
- Tourmaline-bearing rocks in the Singhbhum shear zone, eastern India: Evidence of boron infiltration during regional metamorphism
- High-resolution transmission electron microscopy (HRTEM) study of the 4a and 6a superstructure of bornite Cu5FeS4
- Possible Fe/Cu ordering schemes in the 2a superstructure of bornite (Cu5FeS4)
- TEM-specimen preparation of cell/mineral interfaces by Focused Ion Beam milling
- Direct observation of spinodal decomposition in the magnetite-hercynite system by susceptibility measurements and transmission electron microscopy
- Thermodynamics of uranyl minerals: Enthalpies of formation of rutherfordine, UO2CO3, andersonite, Na2CaUO2(CO3)3(H2O)5, and grimselite, K3NaUO2(CO3)3H2O
- Mixing and ordering behavior in manganocolumbite-ferrocolumbite solid solution: A single-crystal X-ray diffraction study
- Structure change of MgSiO3, MgGeO3, and MgTiO3 ilmenites under compression
- Dehydration processes in the meta-autunite group minerals meta-autunite, metasaléeite, and metatorbernite
- Investigation of the martensitic-like transformation from Mg2GeO4 olivine to its spinel structure polymorph
- A high-temperature diffraction study of the solid solution CaTiOSiO4-CaTiOGeO4
- The vibrational spectrum of synthetic hydrogrossular (katoite) Ca3Al2(O4H4)3: A low-temperature IR and Raman spectroscopic study
- Structural characterization of biogenic Mn oxides produced in seawater by the marine bacillus sp. strain SG-1
- Investigation of smectite hydration properties by modeling experimental X-ray diffraction patterns: Part I. Montmorillonite hydration properties
- Synthesis and crystal-chemistry of alkali amphiboles in the system Na2O-MgO-FeO-Fe2O3- SiO2-H2O as a function of fO2
- Compositional zoning in sphalerite crystals
- Structure and the extent of disorder in quaternary (Ca-Mg and Ca-Na) aluminosilicate glasses and melts
- Makarochkinite, Ca2Fe42+Fe3+TiSi4BeAlO20, a new beryllosilicate member of the aenigmatite-sapphirine-surinamite group from the Ilʼmen Mountains (southern Urals), Russia
- Formation of lava stalactites in the master tube of the 1792-1793 flow field, Mt. Etna (Italy)
- Crystal-size distributions of garnets in metapelites from the northeastern Bushveld contact aureole, South Africa
- Early diagenetic origin of Al phosphate-sulfate minerals (woodhouseite and crandallite series) in terrestrial sandstones, Nova Scotia, Canada
- Scandium silicates from the Baveno and Cuasso al Monte NYF-granites, Southern Alps (Italy): Mineralogy and genetic inferences
- Letter. The effect of Fictive temperature on Al coordination in high-pressure (10 GPa) sodium aluminosilicate glasses
- Letter. α-PbO2-type nanophase of TiO2 from coesite-bearing eclogite in the Dabie Mountains, China
- Letter. Morphological characteristics of ordered kaolinite: Investigation using electron back-scattered diffraction