Synthesis and Characterization of New Quaternary Selenides with ThCr2Si2-Type Structure: ACuMnSe2 (A = K, Rb, Cs)

The new selenides ACuMnSe2 (A = K, Rb, Cs) were synthesized by heating a mixture of the corresponding alkali metal carbonate, copper oxide, manganese, and elemental selenium at 1200 K in hydrogen/argon atmosphere. The dark-gray compounds, moderately air-stable, crystallize in the ThCr2Si2-type structure (space group I4/mmm). Semiconducting properties and short-range antiferromagnetism were observed for all the samples. A comparison of the transport properties with those previously reported for the isostructural sulfides ACuMnS2 (A = K, Rb, Cs) confirmed the primary role of the metal-metal bonds in defining the electronic properties of this series.