The bridging sulfido anions (μ-RS)(μ-S-)[Fe2(CO)6]2(μ4-S) (4a) react with succinyl chloride in THF to give double and quadruple butterfly Fe/S clusters (μ-RS)(μ-RSS)[Fe2(CO)6]2(μ4-S) (5a, R = Et; 6a, R = t-Bu) and [(μ-RS)Fe2(CO)6(μ4-S)Fe2(CO)6]2(μ-S−S-μ) (5b, R = Et; 6b, R = t-Bu), unexpectedly. Crystal structrues of 6a and 6b are described.