Abstract
Fluorosmectites, [M-0.5](inter)[Mg2.5Li0.5](oct)[Si-4](O10F2)-O-tet (M = Na, K, Rb, Cs), have been synthesised from the melt in gastight Mo crucibles. At the same layer charge of x = 0.5, which lies within the range of smectites, both, the crystallite size and the stacking order increases with the size of the interlayer cation. For microcrystalline Na-hectorite both rotational (n120degrees and ...
Abstract
Fluorosmectites, [M-0.5](inter)[Mg2.5Li0.5](oct)[Si-4](O10F2)-O-tet (M = Na, K, Rb, Cs), have been synthesised from the melt in gastight Mo crucibles. At the same layer charge of x = 0.5, which lies within the range of smectites, both, the crystallite size and the stacking order increases with the size of the interlayer cation. For microcrystalline Na-hectorite both rotational (n120degrees and n60degrees) and translational (+/-0.145b) planar defects were identified, whereas for K-hectorite only +/-b/3 translational defects were found. Finally, Rb- and Cs-hectorite show a normal Bragg-type diffraction pat-tern. For Cs-hectorite even single crystals may be found that display no diffuse scattering and allow a structure refinement (monoclinic, 1M-polytype, C2/m, a = 5.2401(10) Angstrom, b = 9.0942(10) Angstrom, c = 10.7971(10) Angstrom, beta = 99.21 (2)degrees, V = 507.90(12). Angstrom(3), Z = 2). These 3D ordered smectites still show satisfactory intracrystalline reactivity and the interlayer cations may readily be exchanged for organocations.
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