The reaction Of [CP2*Rh2Cl4] (CP* = C5Me5) with a slight excess of K3SbS3 in boiling THF gave the neutral clusters [CP*4Rh4S5] (1), [CP*3Rh3Sb2S5] (2), and after salt metathesis [CP*3Rh3SbSn]PF6 (3; n = 5 and 6). The structures of 1-3 are heterocubane clusters with Cp*Rh, S, and Sb vertices but with sulfur inserted into one (11 and 2) or two (3) edges. X-ray diffraction analysis of 2 additionally reveals a very short Sb-S distance of 2.297(l) A within the novel mu(3)-Sb2S4 ligand. Density functional theory calculation of the model compounds [SSbS](3-), [HSSbS](2-), and [HSSbH2S](0) provided strong evidence for the existence of a stable terminal Sb=S double bond in 2.