Home Letter. Si-Al distribution in high-pressure CaAl4Si2O11 phase: A 29Si and 27Al NMR study
Article
Licensed
Unlicensed Requires Authentication

Letter. Si-Al distribution in high-pressure CaAl4Si2O11 phase: A 29Si and 27Al NMR study

  • Xianyu Xue EMAIL logo , Shuangmeng Zhai and Masami Kanzaki
Published/Copyright: April 1, 2015
Become an author with De Gruyter Brill

Abstract

High-resolution 29Si and 27Al NMR techniques have been applied to resolve the Si-Al distribution and coordination in the high-pressure CaAl4Si2O11 (CAS) phase, a potentially important mineral in subducted crustal materials in the deep mantle that has a unique hexagonal ferrite structure containing two octahedral (M1; M2) and one trigonal bipyramidal sites. The 29Si MAS NMR spectra of the CAS phase synthesized at 20 GPa and 1400~1600°C show two broad, asymmetric peaks near -92.7 and -182.7 ppm with an intensity ratio of 1:3, suggesting that 1/4 of the Si are in tetrahedral coordination and 3/4 in octahedral coordination. Therefore, the trigonal bipyramidal and M1 octahedral sites are each occupied by equal proportions of Si and Al, and the former are effectively half-occupied face-sharing tetrahedra (at least for Si). The 27Al MAS and 3Q MAS NMR spectra contain only one unresolved peak typical of octahedral Al with a range of quadrupolar coupling constants

Received: 2009-7-10
Accepted: 2009-7-31
Published Online: 2015-4-1
Published in Print: 2009-11-1

© 2015 by Walter de Gruyter Berlin/Boston

Articles in the same Issue

  1. Review Paper. Microbe-clay mineral interactions
  2. Chemical substitutions, paragenetic relations, and physical conditions of formation of högbomite in the Sittampundi layered anorthosite complex, South India
  3. Miguelromeroite, the Mn analogue of sainfeldite, and redefinition of villyaellenite as an ordered intermediate in the sainfeldite-miguelromeroite series
  4. Mechanism and kinetics of a mineral transformation under hydrothermal conditions: Calaverite to metallic gold
  5. A statistical reassessment of the evidence for the racemic distribution of quartz enantiomorphs
  6. On the crystal structure and crystal chemistry of pollucite, (Cs,Na)16Al16Si32O96·nH2O: A natural microporous material of interest in nuclear technology
  7. The effect of fluid inclusion size on determination of homogenization temperature and density of liquid-rich aqueous inclusions
  8. Effect of SiO2, total FeO, Fe3+/Fe2+, and alkali elements in basaltic glasses on mid-infrared
  9. Influence of cation size on the low-temperature heat capacity of alkaline earth metasilicate glasses
  10. The high-pressure–high-temperature behavior of bassanite
  11. Geochemistry of reversible hydratable tephra from the Trans Mexican Volcanic Belt
  12. Physical contradictions and remedies using simple polythermal equations of state
  13. Thermodynamic and crystallographic properties of kornelite [Fe2(SO4)3·~7.75H2O] and paracoquimbite [Fe2(SO4)3·9H2O]
  14. Humidity-induced phase transitions of ferric sulfate minerals studied by in situ and ex situ X-ray diffraction
  15. In situ Raman spectroscopy of MgSiO3 enstatite up to 1550 K
  16. Optical spectroscopic study of tetrahedrally coordinated Co2+ in natural spinel and staurolite at different temperatures and pressures
  17. New insights into smectite illitization: A zoned K-bentonite revisited
  18. The hydrothermal conversion of kaolinite to kalsilite: Influence of time, temperature, and pH
  19. Sideronatrite, Na2Fe(SO4)2(OH)·3H2O: Crystal structure of the orthorhombic polytype and OD character analysis
  20. Anharmonic OH vibrations in brucite: Small pressure-induced redshift in the range 0–22 GPa
  21. Structural properties of biologically controlled hydrozincite: An HRTEM and NMR spectroscopic study
  22. Mechanism of wollastonite carbonation deduced from micro- to nanometer length scale observations
  23. Letter. Crystal structure of argentopyrite, AgFe2S3, and its relationship with cubanite
  24. Letter. Magnetite-free, yellow lizardite serpentinization of olivine websterite, Canyon Mountain complex, N.E. Oregon
  25. Letter. The influence of atomic size and charge of dissolved species on the diffusivity and viscosity of silicate melts
  26. Letter. Si-Al distribution in high-pressure CaAl4Si2O11 phase: A 29Si and 27Al NMR study
Downloaded on 24.9.2025 from https://www.degruyterbrill.com/document/doi/10.2138/am.2009.3348/html
Scroll to top button