A mixed oxidation-state (Rh-2(4+) and Rh-2(5+)) complex, [{Rh-2(acam)(4)}(2)(mu(4)-ReO4)] (1, Hacam = acetamide), was synthesized and characterized by X-ray structure analysis. A square-sheet structure is constructed from Rh-2(acam)(4) units and ReO4- ion linkers in which all dirhodium units are crystallographically equivalent. In the mixed oxidation-state compounds, the electrical conductivity of 1 (8.9 x 10(-6) S cm(-1)) is higher than that of [{Rh-2(acam)(4)}(3)(mu(3)-Cl)(2)]center dot 4H(2)O, but lower than that of [{Rh-2(acam)(4)}(2)(mu(4)-I)]center dot 6H(2)O.