First example of molybdenum atoms in the network of high temperature Chevrel phases:: Moy[Mo6Se8-xSx]

In the literature Mo6Se8-xSx (0 less than or equal to x less than or equal to 4) Chevrel phase binaries are stable compounds, synthesized by solid state reaction from stoichiometric mixture of MoS2, MoSe2, and Mo powders at 1200 degrees C. We report the single-crystal structure of these compounds, The structural determinations show as expected a classical Chevrel phase structure with a framework of pseudomolecular Mo6Se8-xSx cubic units but furthermore exhibit molybdenum atoms in the channels of the host structure of these compounds, leading to the new formula Mo-y[Mo6Se8-xSx] with 0 less than or equal to x less than or equal to 5 and y similar to 0.3. These extra molybdenum atoms stabilize the Chevrel phase host network and seem to be linking with a molybdenum atom of the Mo, cluster, forming a kind of Mo, cluster. (C) 1999 Academic Press.