Synthesis, Structure, and Electrical Properties of the Mo12 Cluster Sulfide Hg∼2.8KMo12S14 Containing Mercury Chains.

The new compound Hg∼2.8KMo12S14 was synthesized by diffusing mercury into the metastable KMo12S14 compound at 350 °C. Its crystallographic structure, solved from single-crystal X-ray diffraction, shows that the Mo-S framework is maintained during the synthesis. It is based on Mo12S14S6 units interlinked via Mo-S bonds as in the parent compound. The mercury forms linear chains with Hg-Hg distances of about 2.72 Å in the tunnels delimited by the Mo12S14S6 units. Superconductivity was observed below 2.5 K by electrical resistivity and magnetic susceptibility measurements.