Heteroatom framework distribution and layer charge of sodium Taeniolite

The most advanced applications of clays depend crucially on their hydration state and swelling is probably the most important feature of expandable 2:1 layered silicates. Sodium Taeniolite, Na-TAE, a swelling trioctahedral fluormica, has been synthesized and studied using thermogravimetric analysis, X-ray diffraction, scanning electron microscopy and infrared and solid state NMR spectroscopies. The results indicated the formation of a swelling 2:1 phyllosilicate with heteroatoms distribution compatible with Li0.95Na0.53[Si8][Mg4.52Li1.48]O20F4·2.16H2O formula which deviates considerably from the usually quoted ideal composition Na2[Si8][Mg4Li2]O20F4·2.16H2O.163