Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada.
Phys Chem Chem Phys. 2012 May 28;14(20):7375-83. doi: 10.1039/c2cp40764g. Epub 2012 Apr 25.
A series of sodium borosilicate glasses containing cesium, molybdenum, and chromium was prepared to investigate the partitioning of chromium amongst the glass and phase-separated crystalline molybdates. The precipitates were examined by (133)Cs, (23)Na, and (95)Mo MAS NMR, revealing a phase assemblage consisting of Na(2)MoO(4), Na(2)MoO(4)·2H(2)O, Cs(2)MoO(4), Cs(2)CrO(4), CsNaMoO(4)·2H(2)O, and Cs(3)Na(MoO(4))(2). (133)Cs MAS NMR indicates random substitution of Cr into the Mo sites of Cs(3)Na(MoO(4))(2) and provides a quantitative assessment of Cr incorporation. The sample compositions were verified by various analytical techniques and highlight the centrality of NMR in the identification and quantification of heterogeneous crystalline composites, including sensitivity to cationic substitution. The observation and facile interconversion of hydrated phases invites careful consideration of these materials for nuclear waste disposal.
一系列含有铯、钼和铬的硼硅酸钠玻璃被制备出来，以研究铬在玻璃和相分离的结晶钼酸盐之间的分配。沉淀物通过 (133)Cs、(23)Na 和 (95)Mo MAS NMR 进行了检查，揭示了由 Na(2)MoO(4)、Na(2)MoO(4)·2H(2)O、Cs(2)MoO(4)、Cs(2)CrO(4)、CsNaMoO(4)·2H(2)O 和 Cs(3)Na(MoO(4))(2)组成的相组合。(133)Cs MAS NMR 表明 Cr 随机取代 Cs(3)Na(MoO(4))(2)中的 Mo 位，并提供了 Cr 掺入的定量评估。通过各种分析技术验证了样品组成，并强调了 NMR 在识别和量化非均相结晶复合材料中的重要性，包括对阳离子取代的敏感性。水合相的观察和易于相互转化促使人们仔细考虑将这些材料用于核废料处理。
