The anions of complexes Mo~2S~4(i-mnt)~2(Et~4N)~2 and (Et~4N)~3K [Mo~2S~4(i-mnt)~2]~2[i-mnt=S~2C(CN)^2^-] form special chains in the crystals. In this paper, their band structures have been studied by using the tight-binding energy band method within the extended Huckel scheme. It is found that there exist weak interactions between adjacent anions and this kind of interactions is the basis for the formation of the chain. The chain structures are correlated with the semiconducting properties of the crystals. The calculated densities of states and crystal orbital overlap populations show the charge distributions and chemical bonding properties which coincide with the experimental results.

Key words: CLUSTER COMPOUND, ANION, MOLYBDENUM COMPLEX, SULFIDE COMPLEX, BAND STRUCTURES, BAND STRUCTURE CALCULATION, STRUCTURAL BEHAVIOUR, CHAIN STRUCTURE, INTERACTIONS