"Structural studies of hydrated germanium X-type zeolite via Rietveld analysis of synchrotron powder X-ray diffraction data"
G.M. Johnson, Y. Lee, A. Tripathi, J.B. Parise
Microporous and Mesoporous Materials
Vol.31, No.1, pp.195-204, 1999.01
An aluminogermanate analog of zeolite X has been synthesized by solution reaction, and characterized by Rietveld analysis of synchrotron powder X-ray diffraction data. The hydrated sample has a chemical formula Na96Al96Ge96O384·wH2O, and the material possesses an ordered arrangement of Al and Ge in the framework. A cell parameter of 25.589(1) Å confirms the expected cell expansion over Low Silica X (LSX), although a smaller average framework T–O–T bond angle indicates greater relative cell collapse than for LSX. The distribution of sodium cations in the non-framework sites in NaGeX is significantly different from that in LSX, and appears to deviate from the proposed relationship between Al content and cation siting for hydrated aluminosilicate faujasite-type zeolites.