著者

薛 献宇 神崎 正美 Shatskiy Anton

出版者

日本鉱物科学会

雑誌

日本鉱物科学会年会講演要旨集

巻号頁・発行日

vol.2007, pp.130-130, 2007

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We have applied one-dimensional (1D) 1H and 29Si MAS NMR and 1H-29Si cross-polarization (CP) MAS NMR, and 2D 1H NOESY, high-resolution 1H CRAMPS (FSLG)-MAS NMR, 1H double-quantum filtered (DQF) single-quantum (1Q) -1Q correlation MAS NMR and 1H-29Si heteronuclear correlation (HETCOR) NMR techniques to gain new insights into the structure of two phases of potential mantle water reservoir, phase D and superhydrous B. Two samples containing both phases have been synthesized from a mixture of Mg(OH)2 and SiO2 at 24 GPa and 900-1100C. For phase D, the 29Si NMR spectra contain a nearly symmetric, broad peak near -177.7 ppm, attributable to octahedral Si with a disordered local structure. The high-resolution 1H CRAMPS spectra contain a main peak near 12.6 ppm with two shoulders near 10 and 7 ppm, suggesting a disordered proton distribution, mostly with shorter hydrogen bonds than previously suggested. For superhydrous B, our 2D NMR data have clearly revealed that it contains dissimilar proton (H1-H2) pairs and one tetrahedral Si site, consistent with space group Pnn2.