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Optical spectra of Co2+ in three synthetic silicate minerals

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Published/Copyright: March 26, 2015
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American Mineralogist
From the journal American Mineralogist Volume 86 Issue 7-8

Abstract

Polarized optical absorption spectra of three synthetic Co-bearing silicates, orthopyroxene, olivine and beryl, were studied at room and liquid nitrogen temperatures. In all three matrices, Co enters octahedral structural sites as the Co2+ ion. In accordance with the d7 electronic energy level diagram, the spectra show three distinct band systems which are assumed to originate from three spin-allowed dd transitions of Co2+, 4T1g(4F) →4T2g(4F), 4T1g(4F) →4A2g(4F), and 4T1g(4F) →4T1g(4P). The number of bands is different in different matrices and is regulated by the splitting of electronic states, symmetry selection rules for electronic transitions between them, and Co2+ ion distribution between non-equivalent structural sites. Due to a strong preference of Co2+ for the M2 site and the greater intensities (oscillator strengths) of electronic dd transitions for Co2+ in the M2 site, M2 Co2+ bands prevail in the (Mg,Co)SiO3 orthopyroxene spectra. In olivines, the number of bands is larger than in orthopyroxene due to the combined contribution of both M1 Co2+ and M2 Co2+ ions. By comparison of the (Mg,Co)2SiO4 and Co2SiO4 olivine spectra, the bands caused by M1 Co2+ and M2 Co2+ were distinguished. The spectra of Co-bearing beryls, Be3Al2[Si6O18], prepared by both flux and hydrothermal growth, indicate that Co enters the structure mostly as Co2+ in the octahedral Alsite.

Received: 2000-10-13
Accepted: 2001-3-28
Published Online: 2015-3-26
Published in Print: 2001-7-1

© 2015 by Walter de Gruyter Berlin/Boston

Articles in the same Issue

  1. Calcite inclusions in forsterite
  2. The induced thermoluminescence and thermal history of plagioclase feldspars
  3. Characterization and comparison of structural and compositional features of planetary quadrilateral pyroxenes by Raman spectroscopy
  4. A P21/c-C2/c high-pressure phase transition in Ca0.5Mg1.5Si2O6 clinopyroxene
  5. Energy-filtered transmission electron microscopy (EFTEM) of intergrown pyroxenes
  6. TEM analysis of microbial mediated sedimentation and lithification in modern marine stromatolites
  7. Mineralogy of a natural As-rich hydrous ferric oxide coprecipitate formed by mixing of hydrothermal fluid and seawater: Implications regarding surface complexation and color banding in ferrihydrite deposits
  8. A C/MoS2 mixed-layer phase (MoSC) occurring in metalliferous black shales from southern China, and new data on jordisite
  9. Step edges on galena (100): Probing the basis for defect driven surface reactivity at the atomic scale
  10. Solubility study of Ti,Zr-based ceramics designed to immobilize long-lived radionuclides
  11. Characterization of synthetic Cs-Li cancrinite grown in a butanediol-water system: An NMR spectroscopic and Rietveld refinement study
  12. Optical spectra of Co2+ in three synthetic silicate minerals
  13. Spectroscopic standards for four- and fivefold-coordinated Fe2+ in oxygen-based minerals
  14. Hydrous species in crystalline and metamict titanites
  15. First principles study of water adsorption on the (100) surface of zircon: Implications for zircon dissolution
  16. A molecular dynamics study of the glass transition in CaAl2Si2O8: Thermodynamics and tracer diffusion
  17. The crystal structure of aravaipaite
  18. Letter. Feldspar thermometry in ultrahigh-temperature metamorphic rocks: Evidence of crustal metamorphism attaining ~1100 °C in the Archean Napier Complex, East Antarctica
https://doi.org/10.2138/am-2001-0712

Articles in the same Issue

  1. Calcite inclusions in forsterite
  2. The induced thermoluminescence and thermal history of plagioclase feldspars
  3. Characterization and comparison of structural and compositional features of planetary quadrilateral pyroxenes by Raman spectroscopy
  4. A P21/c-C2/c high-pressure phase transition in Ca0.5Mg1.5Si2O6 clinopyroxene
  5. Energy-filtered transmission electron microscopy (EFTEM) of intergrown pyroxenes
  6. TEM analysis of microbial mediated sedimentation and lithification in modern marine stromatolites
  7. Mineralogy of a natural As-rich hydrous ferric oxide coprecipitate formed by mixing of hydrothermal fluid and seawater: Implications regarding surface complexation and color banding in ferrihydrite deposits
  8. A C/MoS2 mixed-layer phase (MoSC) occurring in metalliferous black shales from southern China, and new data on jordisite
  9. Step edges on galena (100): Probing the basis for defect driven surface reactivity at the atomic scale
  10. Solubility study of Ti,Zr-based ceramics designed to immobilize long-lived radionuclides
  11. Characterization of synthetic Cs-Li cancrinite grown in a butanediol-water system: An NMR spectroscopic and Rietveld refinement study
  12. Optical spectra of Co2+ in three synthetic silicate minerals
  13. Spectroscopic standards for four- and fivefold-coordinated Fe2+ in oxygen-based minerals
  14. Hydrous species in crystalline and metamict titanites
  15. First principles study of water adsorption on the (100) surface of zircon: Implications for zircon dissolution
  16. A molecular dynamics study of the glass transition in CaAl2Si2O8: Thermodynamics and tracer diffusion
  17. The crystal structure of aravaipaite
  18. Letter. Feldspar thermometry in ultrahigh-temperature metamorphic rocks: Evidence of crustal metamorphism attaining ~1100 °C in the Archean Napier Complex, East Antarctica
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