Structure of volatile-containing silicate melts by multi-nuclear and multi-quantum NMR spectroscopy

通过多核和多量子核磁共振波谱研究含挥发物的硅酸盐熔体的结构

• 批准号: 14340163
• 负责人: KANZAKI Masami
• 金额: $ 9.41万
• 依托单位: OKAYAMA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14340163/
• 关键词: multi-nuclear NMR spectroscopy; structure of silicate melt; hydrous melt; volatile component; local structure; dissolution mechanism; 多核NMR; ガラス構造; 含水ガラス; 多量子NMR; NMR分光法; マグマ; 高圧; ラマン分光

1.Structure of hydrous glasses : In order to investigate water dissolution mechanisms in silicate melts, we have studied hydrous melts in CaO-MgO-SiO_2 system using-^<29>Si and ^1H MAS NMR and ^1H-^<29>Si CP MAS NMR. We found free OH as well as SiOH and H_2O in these melts. Free OH was not observed in previous studies which are conducted on silica-rich melts. There is systematic changes in abundance of free OH with Mg/Ca and M/Si ratio. From these results, we suggest that free OH could be important in natural ultramafic magmas.2.Structure of sulfur-bearing glasses : In order to study how sulfur dissolves in silicate melts, S-bearing glasses were studied by ^<29>Si MAS NMR and micro-Raman spectroscopy. We synthesized sodium silicate glasses containing sulfur of different valence states (S^0〜S^<6+>). When native S is added, melt structure was polymerized, whereas slightly less polymerized when sulfate is added. No detectable Si-S linkages are found.3.Ab initio calculation of chemical shifts : Using molecular orbital theory, we have calculated wide varieties, of silicate, clusters relevant to melt or glass structures with volatile components. Calculated shifts of^1H and ^<29>Si NMR in hydrous systems support our assignment of free OH observed in the NMR spectra. Similar calculations for NMR and also vibrational spectra help us to identify sulfur species in the sulfur-containing melts.

1.水合玻璃的结构：为了研究硅酸盐熔体中的水溶解机理，我们利用-^<29>Si和^1H MAS NMR以及^1H-^<29>Si CP MAS NMR研究了CaO-MgO-SiO_2体系中的水合熔体。我们在这些熔体中发现了游离的 OH、SiOH 和 H_2O。在之前对富含二氧化硅的熔体进行的研究中没有观察到游离 OH。游离 OH 丰度随 Mg/Ca 和 M/Si 比值发生系统变化。从这些结果中，我们认为游离OH在天然超镁铁质岩浆中可能很重要。2.含硫玻璃的结构：为了研究硫如何在硅酸盐熔体中溶解，通过^ 29 Si MAS NMR和显微拉曼光谱研究了含硫玻璃。我们合成了含有不同价态硫（S^0〜S^<6+>）的硅酸钠玻璃。当添加天然硫时，熔体结构发生聚合，而当添加硫酸盐时，聚合程度稍低。没有发现可检测到的Si-S键。3.化学位移的从头计算：利用分子轨道理论，我们计算了多种硅酸盐、与具有挥发性成分的熔体或玻璃结构相关的簇。含水系统中计算的 1 H 和 29 Si NMR 位移支持我们对 NMR 光谱中观察到的游离 OH 的归属。核磁共振和振动光谱的类似计算有助于我们识别含硫熔体中的硫物质。

项目成果

Mibe, K., M.Kanzaki, T.Kawamoto, K.Matsukage, Y.Fei, S.Ono: "Investigation of critical behavior in basalt-H2O system using High-pressure and high-temperature X-ray radiography"Journal of Geography. 112. 970-978 (2003)

Mibe, K., M.Kanzaki, T.Kawamoto, K.Matsukage, Y.Fei, S.Ono：“利用高压高温 X 射线照相技术研究玄武岩-H2O 系统中的关键行为”Journal of

三部賢治, 神崎正美, 川本竜彦, 松影香子, 費英偉, 小野重明: "高温高圧X線ラジオグラフィ法による玄武岩-H_2O系の臨界状態に関する研究"地学雑誌. 112. 970-978 (2003)

Kenji Sanbe、Masami Kanzaki、Tatsuhiko Kawamoto、Kako Matsukage、Hidetaka Hidetoshi、Shigeaki Ono：“利用高温高压 X 射线照相研究玄武岩-H_2O 系统的临界状态”地球科学杂志 112. 970。 -978 (2003)