Charge Homogeneity in Synthetic Fluorohectorite

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• 作者：Josef Breu ; Wolfgang Seidl ; Alexander J. Stoll ; Kurt G. Lange ; and Thomas U. Probst
• 刊名：Chemistry of Materials
• 出版年：2001
• 出版时间：November 2001
• 年：2001
• 卷：13
• 期：11
• 页码：4213 - 4220
• 全文大小：127K
• 年卷期：v.13,no.11(November 2001)
• ISSN：1520-5002

文摘

Due to phase separation in the silicate melt, the synthesis of fluorosmectites([Na_0.5]^inter[Mg_2.5Li_0.5]^oct[Si₄]^tetO₁₀F₂) from the melt without mechanical mixing yields aninhomogeneous material. Because of the solid solution capability of the 2:1 layer silicatestructure, the nonuniformity in chemical and mineral composition inevitably will lead tofluorosmectites that adopt a range of charge densities. This will be detrimental to manypossible applications due to the large influence of layer charge on the properties of clayminerals. The problem can be circumvented by rotating the crucible during synthesis in ahorizontal mounting, which will continuously force mixing of the melt mechanically. Theproduct obtained is homogeneous at all length scales as judged by chemical analysis and itsuniform intracrystalline reactivity. Noteworthy is its tendency to form regularly interstratified intercalates of monolayers and bilayers upon alkylammonium exchange and of rectoritetype phases upon partial K⁺ exchange. We expect that the two dissimilar types of galleries,which are stacked in a regularly alternating pattern, can be selectively addressed-leadingto interesting intercalation materials.