A Simple Access to Pure Thorium(IV) Halides (ThCl4, ThBr4, and ThI4)

In this work we present a facile, lab scale synthesis for thorium tetrahalides ThX4 (X = Cl, Br, and I). The reaction between the easily available ThO2 and AlX3 (X = Cl, Br, and I) and a subsequent in situ chemical vapor transport (CVT) leads to a product of high purity, which is obtained in the form of crystals or large aggregates of crystals. Their identity and purity was evidenced by X-ray powder diffraction and IR spectroscopy. The usage of ThO2 avoids, unlike earlier syntheses, the utilization of scarcely available thorium metal or of other reactants, such as CCl4, which leads to impurities. Furthermore, the reaction tolerates even less pure ThO2.