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Study of cation order-disorder in MgAl2O4spinel by in situ neutron diffraction up to 1600 K and 3.2 GPa

  • Fabienne Méducin EMAIL logo , Simon A.T. Redfern , Yann Le Godec , Howard J. Stone , Matt G. Tucker , Martin T. Dove and William G. Marshall
Published/Copyright: March 28, 2015
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American Mineralogist
From the journal American Mineralogist Volume 89 Issue 7

Abstract

The temperature-dependence of the cation distribution in synthetic spinel (MgAl2O4) was investigated using in situ time-of-flight neutron powder diffraction at ISIS, the pulsed-neutron source at the Rutherford Appleton Laboratory. Neutron diffraction patterns of stoichiometric MgAl2O4 were collected on heating from room temperature to ∼1600 K at pressures of ∼2.6 GPa. The cation distribution was determined directly from site occupancies obtained by Rietveld refinement. The equilibrium non-convergent ordering was analyzed using the OʼNeill-Navrotsky (1983) thermodynamic model, which fits the observed behavior well over the temperature range of the measurements. Fitting the data between 790 and 1600 K yields α = 31(6) kJ/mol and β = -20(13) kJ/mol in the expression for the free energy of ordering. The high-pressure temperature-dependent behavior, as compared to equivalent ambient-pressure behavior, demonstrates that disordering occurs to a much greater extent in MgAl2O4 at high pressure and that pressure favors disordering toward the inverse structure.

Received: 2003-6-13
Accepted: 2004-1-6
Published Online: 2015-3-28
Published in Print: 2004-7-1

© 2015 by Walter de Gruyter Berlin/Boston

Articles in the same Issue

  1. Hydroxyl in omphacites and omphacitic clinopyroxenes of upper mantle to lower crustal origin beneath the Siberian platform
  2. Structural variations induced by difference of the inert pair effect in the stibnite-bismuthinite solid solution series (Sb,Bi)2S3
  3. Hydrogen solubility and speciation in natural, gem-quality chromian diopside
  4. Ultrastructure, aggregation-state, and crystal growth of biogenic nanocrystalline sphalerite and wurtzite
  5. Impactite from Henbury, Australia
  6. Neutron and synchrotron X-ray diffraction study of the structures and dehydration behaviors of ramsdellite and “groutellite”
  7. Hydrothermal synthesis and crystal chemistry of the new strontium uranyl selenites, Sr[(UO2)3(SeO3)2O2]⋅4H2O and Sr[UO2(SeO3)2]
  8. Study of cation order-disorder in MgAl2O4spinel by in situ neutron diffraction up to 1600 K and 3.2 GPa
  9. Magnetic granulometry from equilibrium magnetization measurements: Mineral magnetometry of superparamagnetic particles and application to synthetic ferrihydrites
  10. Hydroxide in kyanite: A quantitative determination of the absolute amount and calibration of the IR spectrum
  11. Analysis of uranyl-bearing phases by EXAFS spectroscopy: Interferences, multiple scattering, accuracy of structural parameters, and spectral differences
  12. X-ray diffraction evidence for a monoclinic form of stibnite, Sb2S3, below 290 K
  13. Sulfur species at chalcopyrite (CuFeS2) fracture surfaces
  14. Dehydration and rehydration process in boggsite: An in situ X-ray single-crystal study
  15. Empressite, AgTe, from the Empress-Josephine mine, Colorado, U.S.A.: Composition, physical properties, and determination of the crystal structure
  16. Correlation of pH-dependent surface interaction forces to amino acid adsorption: Implications for the origin of life
  17. A near-infrared spectroscopic study of hydroxyl in natural chondrodite
  18. High-pressure elasticity of a natural magnetite crystal
  19. Isotopic and chemical alteration of zircon by metamorphic fluids: U-Pb age depth-profiling of zircon crystals from Barrowʼs garnet zone, northeast Scotland
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  22. Pyrophyllite dehydroxylation process by First Principles calculations
  23. Plagioclase from planetary basalts: Chemical signatures that reflect planetary volatile budgets, oxygen fugacity, and styles of igneous differentiation
  24. The structure of the manganese oxide on the sheath of the bacterium Leptothrix discophora: An XAFS study
  25. An X-ray Rietveld study of piemontite on the join Ca2Al3Si3O12(OH)–Ca2Mn33+Si3O12(OH) formed by hydrothermal synthesis
  26. Raman spectroscopy of basic copper(II) and some complex copper(II) sulfate minerals: Implications for hydrogen bonding
  27. Incorporation of sodium into the chlorite structure: the crystal structure of glagolevite, Na(Mg,Al)6[Si3AlO10](OH,O)8
  28. Cation disorder in dolomite, CaMg(CO3)2, and its influence on the aragonite + magnesite ↔ dolomite reaction boundary
https://doi.org/10.2138/am-2004-0708

Articles in the same Issue

  1. Hydroxyl in omphacites and omphacitic clinopyroxenes of upper mantle to lower crustal origin beneath the Siberian platform
  2. Structural variations induced by difference of the inert pair effect in the stibnite-bismuthinite solid solution series (Sb,Bi)2S3
  3. Hydrogen solubility and speciation in natural, gem-quality chromian diopside
  4. Ultrastructure, aggregation-state, and crystal growth of biogenic nanocrystalline sphalerite and wurtzite
  5. Impactite from Henbury, Australia
  6. Neutron and synchrotron X-ray diffraction study of the structures and dehydration behaviors of ramsdellite and “groutellite”
  7. Hydrothermal synthesis and crystal chemistry of the new strontium uranyl selenites, Sr[(UO2)3(SeO3)2O2]⋅4H2O and Sr[UO2(SeO3)2]
  8. Study of cation order-disorder in MgAl2O4spinel by in situ neutron diffraction up to 1600 K and 3.2 GPa
  9. Magnetic granulometry from equilibrium magnetization measurements: Mineral magnetometry of superparamagnetic particles and application to synthetic ferrihydrites
  10. Hydroxide in kyanite: A quantitative determination of the absolute amount and calibration of the IR spectrum
  11. Analysis of uranyl-bearing phases by EXAFS spectroscopy: Interferences, multiple scattering, accuracy of structural parameters, and spectral differences
  12. X-ray diffraction evidence for a monoclinic form of stibnite, Sb2S3, below 290 K
  13. Sulfur species at chalcopyrite (CuFeS2) fracture surfaces
  14. Dehydration and rehydration process in boggsite: An in situ X-ray single-crystal study
  15. Empressite, AgTe, from the Empress-Josephine mine, Colorado, U.S.A.: Composition, physical properties, and determination of the crystal structure
  16. Correlation of pH-dependent surface interaction forces to amino acid adsorption: Implications for the origin of life
  17. A near-infrared spectroscopic study of hydroxyl in natural chondrodite
  18. High-pressure elasticity of a natural magnetite crystal
  19. Isotopic and chemical alteration of zircon by metamorphic fluids: U-Pb age depth-profiling of zircon crystals from Barrowʼs garnet zone, northeast Scotland
  20. A novel approach to determine high-pressure high-temperature fluid and melt compositions using diamond-trap experiments
  21. Lindbergite, a new Mn oxalate dihydrate from Boca Rica mine, Galiléia, Minas Gerais, Brazil, and other occurrences
  22. Pyrophyllite dehydroxylation process by First Principles calculations
  23. Plagioclase from planetary basalts: Chemical signatures that reflect planetary volatile budgets, oxygen fugacity, and styles of igneous differentiation
  24. The structure of the manganese oxide on the sheath of the bacterium Leptothrix discophora: An XAFS study
  25. An X-ray Rietveld study of piemontite on the join Ca2Al3Si3O12(OH)–Ca2Mn33+Si3O12(OH) formed by hydrothermal synthesis
  26. Raman spectroscopy of basic copper(II) and some complex copper(II) sulfate minerals: Implications for hydrogen bonding
  27. Incorporation of sodium into the chlorite structure: the crystal structure of glagolevite, Na(Mg,Al)6[Si3AlO10](OH,O)8
  28. Cation disorder in dolomite, CaMg(CO3)2, and its influence on the aragonite + magnesite ↔ dolomite reaction boundary
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