Solvothermal synthesis and crystal structure of aluminogermanate halide sodalites using organic solvent

Abstract

Solvothermal synthesis has been investigated for the crystallization of aluminogermanate sodalite containing halide (Cl, Br and I) in 50% ethyl alcohol at low temperature. It was found that 50% ethanol+ 50% water is good solvent system for sodalite. X-ray powder diffraction, IR, ²⁷Al and ²³Na MAS NMR, SEM and thermogravimetry are used to characterize these sodalites. The crystal structures show cubic symmetry in a space group P <img src='http://www.niscair.res.in/jinfo/four.gif' border=0> 3n and were refined by Rietveld refinement method. The unit cell parameter, <i style="mso-bidi-font-style:normal">a</i> = 9.0641, 9.1049 and 9.1874Å and the corresponding Al-O-Ge angles are found to be 133.702, 135.346 and 137.628<span style="font-family:Symbol; mso-ascii-font-family:" times="" new="" roman";mso-hansi-font-family:"times="" roman";="" mso-char-type:symbol;mso-symbol-font-family:symbol"="" lang="EN-GB">° for chloro, bromo and iodo sodalite,respectively. The MAS NMR study confirms alternating Al and Ge ordering of sodalite framework. The thermal stability of guest anions in the sodalite framework was studied by thermogravimetric analysis.

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