The crystal structure of ZSM-10, a powder X-ray and electron diffraction study

Abstract

Abstract The crystal structure of the aluminosilicate, ZSM-10 (T108O216, where T = Si, Al), has been determined from electron diffraction and powder X-ray diffraction data. The material crystallizes in space group P6/mmm, where a = 31.390(2), c = 7.5147(8) Å. The framework [001] projection was determined independently with 300 kV precession electron diffraction amplitudes by direct methods. T-site positions in this projection were consistent with two models proposed in 1996 by Higgins and Schmitt. Subsequent Rietveld refinement favors their model A, comprising stacked cancrinite cages and hexagonal prisms. The framework density is 16.6 T sites/1000 Å3, similar to zeolite framework LTL. However, the refinement against synchrotron data from a dehydrated sample (R wp = 0.1600, R(F 2) = 0.1418) finds no extra-framework species, despite the detection of some K+ in the material.