Abstract: The title compound {Mo[S₂CN( C₂H₅)₂]₄}⁺¹MoCl₆}^-1was synthesized,and its crystal structure was determined by X-ray diffraction.It is nionoclinic,space group P2₁/a with a=14.761(6)Å b=16.012(6)Å,c=17.108(9)Å,β=102.63(4) and Z=4.The coordinates of a molybdenum atom were deduced from the Patterson function,and parameters of other atoms were found from successive Fourier syntheses.The block-diagonal least-siuares refinement for all alons gave final residual factors R=0.0908,R_w=0.0761.