Ab initio calculation of 29Si NMR chemical shifts for the clusters of Si(OH)4, Si(OH)5- and Si(OH)6-2.

• KANZAKI Masami

  Department of Mechanical Sciences Tokyo, Institute of Technology

抄録

In order to identify five-coordinated Si(Si^v) species in crystalline and amorphous silicates by NMR spectroscopy, ²⁹Si NMR chemical shifts for the clusters of Si(CH₃)₄ (TMS), Si(OH)₄, Si(OH)₅⁻ and Si(OH)₆⁻² were calculated using ab initio molecular orbital theory. The calculated shifts relative to TMS cluster were −71.7 and −179.0 ppm for Si(OH)₄ and Si(OH)₆⁻², respectively, and are in good agreement with observed shifts. The calculated shift for Si(OH)₅⁻ was −127.4 ppm, falls just between the shifts of Si(OH)₄ and Si(OH)₆⁻². The chemical shift for Si^v species in polymerized silicates is expected to appear at about −150 ppm, if the effect of polymerization is considered. Present calculation thus supports the assignment of −150 ppm peak as Si^v species, which has been found in the alkali-silicate glasses quenched from high pressures.

収録刊行物

• Ｍｉｎｅｒａｌｏｇｉｃａｌ　Ｊｏｕｒｎａｌ

  Ｍｉｎｅｒａｌｏｇｉｃａｌ　Ｊｏｕｒｎａｌ 18 (1), 1-8, 1996

  一般社団法人　日本鉱物科学会

キーワード

• General Earth and Planetary Sciences
• General Environmental Science

詳細情報

• CRID: 1390001206546177280
• NII論文ID: 10008772579
• NII書誌ID: AA00739590
• DOI: 10.2465/minerj.18.1
• ISSN: 18814174
• ISSN: 05442540
• 本文言語コード: en
• データソース種別:
  • JaLC
  • Crossref
  • CiNii Articles
• 抄録ライセンスフラグ: 使用不可