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Ca2SiO3OHF—A high-pressure phase with dense calcium polyhedral packing and tetrahedral silicon

  • Kurt Leinenweber EMAIL logo , Jennifer E. Johnson and Thomas L. Groy
Published/Copyright: March 28, 2015
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American Mineralogist
From the journal American Mineralogist Volume 90 Issue 1

Abstract

The composition and structure of a new phase crystallizing in high-pressure experiments in the system CaO-Ca(OH)2-CaF2-SiO2 are described. The composition is on the join Ca2SiO3(OH)2-Ca2SiO3F2, with the relative amounts of OH and F near 50/50 from electron probe microanalysis, or near the ideal midpoint composition Ca2SiO3OHF. The symmetry is monoclinic, space group P21/c, with a = 5.8111(7), b = 10.6050(13), and c = 6.6968(8) Å, and β = 102.025(3)°, V = 403.65(8) Å3, Z = 4. In the structure isolated SiO3OH tetrahedral groups occupy narrow linear channels whose axes lie along a. The channels are lined by two types of eight-coordinated CaO5OHF2 polyhedra that share edges and faces. The axes of the channels lie on a nearly hexagonal array in the b-c plane, leading to a cp/b ratio of 0.618, close to the ideal ratio of 0.577 for a hexagonal array. However, there is no simple packing rule for either the cation or anion array. Although the channels are arranged in a nearly hexagonal fashion, the overall symmetry of the structure is not hexagonal, but instead has 5-rings of calcium polyhedra around the channels. The calcium atoms lie on a 5-3-5-3 net of triangles and pentagons that can be compared to the α-U3O8 net.

Received: 2003-10-23
Accepted: 2004-6-13
Published Online: 2015-3-28
Published in Print: 2005-1-1

© 2015 by Walter de Gruyter Berlin/Boston

Articles in the same Issue

  1. Contact metamorphism of the White Mountain Peak metavolcanic complex, eastern California
  2. Structure and luminescence characteristics of quartz from pegmatites
  3. Evidence for monazite-, barite-, and AgMnO4 (distorted barite)-type structures of CaSO4 at high pressure and temperature
  4. The “template” effect of the extra-framework content on zeolite compression: The case of yugawaralite
  5. The influence of OH in coesite on the kinetics of the coesite-quartz phase transition
  6. First-principles study of hydrogen bond symmetrization of phase D under high pressure
  7. First-principles study of OH-stretching modes in kaolinite, dickite, and nacrite
  8. A systematic study of OH in hydrous wadsleyite from polarized FTIR spectroscopy and single-crystal X-ray diffraction: Oxygen sites for hydrogen storage in Earthʼs interior
  9. Determination of the content and distribution of fixed ammonium in illite-smectite using a modified X-ray diffraction technique: Application to oil source rocks of western Greenland
  10. Determination of defect structures in kaolin minerals by high-resolution transmission electron microscopy (HRTEM)
  11. Mössbauer spectroscopy of omphacite and garnet pairs from eclogites: Application to geothermobarometry
  12. Allanite and epidote weathering at the Coweeta Hydrologic Laboratory, western North Carolina, U.S.A.
  13. Ca2SiO3OHF—A high-pressure phase with dense calcium polyhedral packing and tetrahedral silicon
  14. Relationships between SEM-cathodoluminescence response and trace-element composition of hydrothermal vein quartz
  15. Quantitative evaluation of attenuation contrast of X-ray computed tomography images using monochromatized beams
  16. Biotic and abiotic products of Mn(II) oxidation by spores of the marine Bacillus sp. strain SG-1
  17. The Mn, Mg-intracrystalline exchange reaction in donpeacorite (Mn0.54Ca0.03Mg1.43Si2O6) and its relation to the fractionation behavior of Mn in Fe, Mg-orthopyroxene
  18. Crystal structures of chalcostibite (CuSbS2) and emplectite (CuBiS2): Structural relationship of stereochemical activity between chalcostibite and emplectite
  19. Hydration and swelling of synthetic Na-saponites: Influence of layer charge
  20. Dehydroxylation and CO2 incorporation in annealed mica (sericite): An infrared spectroscopic study
  21. Relict coesite exsolution in omphacite from Western Tianshan eclogites, China
  22. Hyperfine electric field gradients and local distortion environments of octahedrally coordinated Fe2+
  23. A synchrotron Mössbauer spectroscopy study of (Mg,Fe)SiO3 perovskite up to 120 GPa
  24. Temporal stability and pressure calibration of barium carbonate and talc/pyrex pressure media in a piston-cylinder apparatus
  25. Cation ordering in magnesioferrite, MgFe2O4, to 982 °C using in situ synchrotron X-ray powder diffraction
  26. Halite-sylvite thermoconsolution
  27. The role of water in the structures of synthetic hallimondite, Pb2[(UO2)(AsO4)2](H2O)n and synthetic parsonsite, Pb2[(UO2)(PO4)2](H2O)n, 0 ≤ n ≤ 0.5
  28. Variable-temperature structural studies of tetranatrolite from Mt. Saint-Hilaire: Synchrotron X-ray powder diffraction and Rietveld analysis
  29. Letter. Pressure-induced stabilization of ordered paranatrolite: A new insight into the paranatrolite controversy
  30. Letter. The effect of zinc sulfide on phase transformations of ferrihydrite
  31. Letter. Stability and equation of state of MgGeO3 post-perovskite phase
  32. Letter. Pressure dependence of the OH-stretching mode in F-rich natural topaz and topaz-OH
https://doi.org/10.2138/am.2005.1528

Articles in the same Issue

  1. Contact metamorphism of the White Mountain Peak metavolcanic complex, eastern California
  2. Structure and luminescence characteristics of quartz from pegmatites
  3. Evidence for monazite-, barite-, and AgMnO4 (distorted barite)-type structures of CaSO4 at high pressure and temperature
  4. The “template” effect of the extra-framework content on zeolite compression: The case of yugawaralite
  5. The influence of OH in coesite on the kinetics of the coesite-quartz phase transition
  6. First-principles study of hydrogen bond symmetrization of phase D under high pressure
  7. First-principles study of OH-stretching modes in kaolinite, dickite, and nacrite
  8. A systematic study of OH in hydrous wadsleyite from polarized FTIR spectroscopy and single-crystal X-ray diffraction: Oxygen sites for hydrogen storage in Earthʼs interior
  9. Determination of the content and distribution of fixed ammonium in illite-smectite using a modified X-ray diffraction technique: Application to oil source rocks of western Greenland
  10. Determination of defect structures in kaolin minerals by high-resolution transmission electron microscopy (HRTEM)
  11. Mössbauer spectroscopy of omphacite and garnet pairs from eclogites: Application to geothermobarometry
  12. Allanite and epidote weathering at the Coweeta Hydrologic Laboratory, western North Carolina, U.S.A.
  13. Ca2SiO3OHF—A high-pressure phase with dense calcium polyhedral packing and tetrahedral silicon
  14. Relationships between SEM-cathodoluminescence response and trace-element composition of hydrothermal vein quartz
  15. Quantitative evaluation of attenuation contrast of X-ray computed tomography images using monochromatized beams
  16. Biotic and abiotic products of Mn(II) oxidation by spores of the marine Bacillus sp. strain SG-1
  17. The Mn, Mg-intracrystalline exchange reaction in donpeacorite (Mn0.54Ca0.03Mg1.43Si2O6) and its relation to the fractionation behavior of Mn in Fe, Mg-orthopyroxene
  18. Crystal structures of chalcostibite (CuSbS2) and emplectite (CuBiS2): Structural relationship of stereochemical activity between chalcostibite and emplectite
  19. Hydration and swelling of synthetic Na-saponites: Influence of layer charge
  20. Dehydroxylation and CO2 incorporation in annealed mica (sericite): An infrared spectroscopic study
  21. Relict coesite exsolution in omphacite from Western Tianshan eclogites, China
  22. Hyperfine electric field gradients and local distortion environments of octahedrally coordinated Fe2+
  23. A synchrotron Mössbauer spectroscopy study of (Mg,Fe)SiO3 perovskite up to 120 GPa
  24. Temporal stability and pressure calibration of barium carbonate and talc/pyrex pressure media in a piston-cylinder apparatus
  25. Cation ordering in magnesioferrite, MgFe2O4, to 982 °C using in situ synchrotron X-ray powder diffraction
  26. Halite-sylvite thermoconsolution
  27. The role of water in the structures of synthetic hallimondite, Pb2[(UO2)(AsO4)2](H2O)n and synthetic parsonsite, Pb2[(UO2)(PO4)2](H2O)n, 0 ≤ n ≤ 0.5
  28. Variable-temperature structural studies of tetranatrolite from Mt. Saint-Hilaire: Synchrotron X-ray powder diffraction and Rietveld analysis
  29. Letter. Pressure-induced stabilization of ordered paranatrolite: A new insight into the paranatrolite controversy
  30. Letter. The effect of zinc sulfide on phase transformations of ferrihydrite
  31. Letter. Stability and equation of state of MgGeO3 post-perovskite phase
  32. Letter. Pressure dependence of the OH-stretching mode in F-rich natural topaz and topaz-OH
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