Cs10Tl6SiO4, Cs10Tl6GeO4, and Cs10Tl6SnO3 – First Oxotetrelate Thallides, Double Salts Containing “Hypoelectronic” [Tl6]6– Clusters

Abstract

AbstractCs10Tl6TtO4 (Tt = Si, Ge) and Cs10Tl6SnO3 were synthesized by the reaction of appropriate starting materials at 623–673 K, followed by fast cooling or quenching to room temperature, in arc‐welded tantalum ampoules. According to single‐crystal X‐ray analyses, the compounds crystallize in new structure types (Cs10Tl6TtO4 (Tt = Si, Ge), P21/c and Cs10Tl6SnO3, Pnma), consisting of [Tl6]6– clusters, which can be characterized as distorted octahedra compressed along one of the fourfold axes of an originally unperturbed octahedron, and [SiO4]4–, [GeO4]4– or [SnO3]4– anions. The oxotetrelate thallides can be regarded as “double salts”, which consist of Cs6Tl6 on one side and respective oxosilicates, ‐germanates and ‐stannates on the other, showing almost not any direct interaction between the two anionic moieties, as might be expressed e.g. by the formula [Cs6Tl6][Cs4SiO4]. In contrast to the silicon and germanium compounds, where the oxidation state of the tetrel atom is unambiguously 4+, for the threefold coordinated tin atom in Cs10Tl6SnO3 an oxidation state of 2+ has to be assumed. Thus, the latter reveal further evidence that the so called “hypoelectronic” [Tl6]6– cluster does not require additional electrons and is intrinsically stable. The distortion of [Tl6]6– can be understood in terms of the Jahn–Teller theorem. According to magnetic measurements all title compounds are diamagnetic.