RESUMO
Ag2[W6I14] and A2- x[W6I14] compounds with A = Na, Li were prepared from binary tungsten iodides (W3I12) and corresponding metal iodides. Their crystal structures are analyzed on the basis of X-ray diffraction data. 7Li and 23Na solid-state NMR measurements reveal that Li+ and Na+ ions are distributed over two sites in the respective structures. These results shed some new light on A x[M6I14] with A = alkali and M = Mo, W compounds being reported with x = 1 and 2, which exhibit photophysical properties. The lithium compound is an exception in the series of A2- x[W6I14] compounds, because it is the only compound which is soluble in water.
RESUMO
The reduction of tungsten hexachloride with lead powder was investigated by differential scanning calorimetry (DSC) combined with X-ray diffraction (XRD) studies. Intermediate compounds along the way of the reduction of W6+ to W2+ were detected, prepared by solid-state synthesis, and structurally characterized by X-ray diffraction techniques. Five new compounds, namely Pb0.5WCl6, PbW2Cl10, Pb1.5[W3Cl13], Pb2Cl[W3Cl13], and Pb[W6Cl14] are discovered to be formed with increasing temperature, and structurally characterized within this study. The analysis of the reduction pathway is meant to gain a better understanding of the metallothermic reduction process and intercalation chemistry in the solid state.
