Article
Licensed
Unlicensed Requires Authentication

Letter. An isosymmetric phase transition of orthopyroxene found by high-temperature X-ray diffraction

  • EMAIL logo , , , and
Published/Copyright: April 1, 2015
Become an author with De Gruyter Brill
Author Information
American Mineralogist
From the journal American Mineralogist Volume 93 Issue 10

Abstract

High-temperature synchrotron X-ray powder diffraction experiments for the composition of (Ca0.06Mg1.94)Si2O6 have been carried out in the present study to clarify whether orthopyroxene has a transition between low- and high-temperature phases. Our results show that discontinuous changes of unit-cell dimensions and volume occur at 1170 °C during both heating and cooling processes and that the space group of Pbca does not change during this reversible phase transition. These facts indicate a first-order and isosymmetric phase transition. This high-temperature phase is thermodynamically distinct from the low-temperature phase, i.e., orthoenstatite in the Mg-rich portion of Mg2Si2O6- CaMgSi2O6 phase diagram, although they have the same space group.

Keywords: Orthopyroxene; isosymmetric phase transition; in-situ X-ray experiments; enstatitediopside system
Received: 2008-5-14
Accepted: 2008-7-7
Published Online: 2015-4-1
Published in Print: 2008-10-1

© 2015 by Walter de Gruyter Berlin/Boston

Articles in the same Issue

  1. Amorphous materials: Properties, structure, and durability: Atomic structure and transport properties of MgO-Al2O3 melts: A molecular dynamics simulation study
  2. Amorphous Materials: Properties, structure, and durability: Oxidation state of iron in hydrous phono-tephritic melts
  3. Amorphous materials: Properties, structure, and durability: Quantitative Raman spectroscopy: Speciation of Na-silicate glasses and melts
  4. Dissolution-reprecipitation of zircon at low-temperature, high-pressure conditions (Lanzo Massif, Italy)
  5. High-pressure behavior of gypsum: A single-crystal X-ray study
  6. Presence and zoning of hydrous components in leucite from the Alban Hills volcano, Rome, Italy
  7. Herderite from Mogok, Myanmar, and comparison with hydroxyl-herderite from Ehrenfriedersdorf, Germany
  8. Application of Raman spectroscopy to quantify trace water concentrations in glasses and garnets
  9. Neutron diffraction study of δ-AlOOD at high pressure and its implication for symmetrization of the hydrogen bond
  10. A simple predictive model for the thermal expansion of AlSi3 feldspars
  11. New data on PGE alloy minerals from a very old collection (probably 1890s), California
  12. High-pressure study on lead fluorapatite
  13. High-pressure Al-rich hexagonal phases—What are their kin?
  14. Leucite at high pressure: Elastic behavior, phase stability, and petrological implications
  15. Thermodynamic mixing properties of Rb-K feldspars
  16. Demicheleite, BiSBr, a new mineral from La Fossa crater, Vulcano, Aeolian Islands, Italy
  17. A lattice dynamical study of the aragonite and post-aragonite phases of calcium carbonate rock
  18. Water in natural olivine—determined by proton-proton scattering analysis
  19. Factors affecting heat transfer in natural SiO2 solids
  20. A solution model for high-temperature PbS-AgSbS2-AgBiS2 galena
  21. Incorporation of molybdate anion into β-FeOOH
  22. Disordering of Fe2+ over octahedrally coordinated sites of tourmaline
  23. Raman spectroscopy of CaIrO3 postperovskite up to 30 GPa
  24. The thermal behavior of richterite
  25. The crystal structure of kelyanite, (Hg2)6(SbO6)BrCl2
  26. Comparison of crystallographic orientations between living (Emiliania huxleyi and Gephyrocapsa oceanica) and fossil (Watznaueria barnesiae) coccoliths using electron microscopes
  27. Letter. Iron partitioning between perovskite and post-perovskite: A transmission electron microscope study
  28. Letter. An isosymmetric phase transition of orthopyroxene found by high-temperature X-ray diffraction
https://doi.org/10.2138/am.2008.3019
Keywords for this article
Orthopyroxene; isosymmetric phase transition; in-situ X-ray experiments; enstatitediopside system

Articles in the same Issue

  1. Amorphous materials: Properties, structure, and durability: Atomic structure and transport properties of MgO-Al2O3 melts: A molecular dynamics simulation study
  2. Amorphous Materials: Properties, structure, and durability: Oxidation state of iron in hydrous phono-tephritic melts
  3. Amorphous materials: Properties, structure, and durability: Quantitative Raman spectroscopy: Speciation of Na-silicate glasses and melts
  4. Dissolution-reprecipitation of zircon at low-temperature, high-pressure conditions (Lanzo Massif, Italy)
  5. High-pressure behavior of gypsum: A single-crystal X-ray study
  6. Presence and zoning of hydrous components in leucite from the Alban Hills volcano, Rome, Italy
  7. Herderite from Mogok, Myanmar, and comparison with hydroxyl-herderite from Ehrenfriedersdorf, Germany
  8. Application of Raman spectroscopy to quantify trace water concentrations in glasses and garnets
  9. Neutron diffraction study of δ-AlOOD at high pressure and its implication for symmetrization of the hydrogen bond
  10. A simple predictive model for the thermal expansion of AlSi3 feldspars
  11. New data on PGE alloy minerals from a very old collection (probably 1890s), California
  12. High-pressure study on lead fluorapatite
  13. High-pressure Al-rich hexagonal phases—What are their kin?
  14. Leucite at high pressure: Elastic behavior, phase stability, and petrological implications
  15. Thermodynamic mixing properties of Rb-K feldspars
  16. Demicheleite, BiSBr, a new mineral from La Fossa crater, Vulcano, Aeolian Islands, Italy
  17. A lattice dynamical study of the aragonite and post-aragonite phases of calcium carbonate rock
  18. Water in natural olivine—determined by proton-proton scattering analysis
  19. Factors affecting heat transfer in natural SiO2 solids
  20. A solution model for high-temperature PbS-AgSbS2-AgBiS2 galena
  21. Incorporation of molybdate anion into β-FeOOH
  22. Disordering of Fe2+ over octahedrally coordinated sites of tourmaline
  23. Raman spectroscopy of CaIrO3 postperovskite up to 30 GPa
  24. The thermal behavior of richterite
  25. The crystal structure of kelyanite, (Hg2)6(SbO6)BrCl2
  26. Comparison of crystallographic orientations between living (Emiliania huxleyi and Gephyrocapsa oceanica) and fossil (Watznaueria barnesiae) coccoliths using electron microscopes
  27. Letter. Iron partitioning between perovskite and post-perovskite: A transmission electron microscope study
  28. Letter. An isosymmetric phase transition of orthopyroxene found by high-temperature X-ray diffraction
Downloaded on 15.4.2026 from https://www.degruyterbrill.com/document/doi/10.2138/am.2008.3019/html
Scroll to top button