Two new Mo compounds, Tl2Mo9S11 and K2Mo9S11, have been found. The structure of these compounds is characterized by the presence of a completely new building block, Mo12S14, in addition to the well-known Mo6S8 unit as in the PbMo6S8-type compounds. The new cluster, Mo12, contained in the Mo12S14 unit can be considered as a one-dimensional condensation of three Mo6 octahedral clusters. These new materials, the structure of which resembles that of PbMo6S8, are metallic but are not superconducting above 2.1°K.
