Cationic and anionic bismuth(III) in chloro-thiourea complexes: crystal structure of [Bi(tu)6][Bi{(tu)1.5Cl1.5}Cl3]2(tu = thiourea)

The structure of the title compound (I) has been solved from diffractometer data by the heavy-atom technique and refined by least-squares methods to R 0.043 for 1 513 observed reflections. Crystals are rhombohedral, with unitcell dimensions a= 13.54(1), c= 7.07(1)Å. The structure consists of [Bi{(tu)1.5Cl1.5}Cl3]3/2–(tu = thiourea) anions, in which there is disorder involving thiourea and chlorine atoms, and [Bi(tu)6]3+ cations. In both ions bismuth atoms occupy special positions in space group P and bond octahedrally to thiourea and (or) chlorine ions. A detailed comparison between this compound and 3BiCl3·7tu is made.