[en] The clusters Re₂(CO)₈[μ-SnXRe(CO)₅]2 are prepared by reaction of Re₂(CO)₁₀ and SnX₂ in a Schlenk-tube under release of pressure (X = Cl, Br, I) or in a sealed glass tube (X = Br, I). As central structural unit a four-membered Re₂Sn₂ ring has to be assumed. This unit can be opened again by reaction with CO under pressure. X₂Sn[Re(CO)₅]₂, which is also formed during the preparation of the clusters in dependence of the CO-pressure, indicates insertion of SnX₂ into the Re-Re bond to be the primary step. The corresponding clusters M₂(CO)₈[μ-GeXM(CO)₅]₂ (M = Mn, X = Br, I; M = Re, X = I) are prepared by reaction of GeI₂ and M₂(CO)₁₀ or I₂Ge[Mn(CO)₅]₂ and Mn₂(CO)₁₀ or of Br₃GeMn(CO)₅ and BrMn(CO)₅. IR frequencies of the new clusters are assigned. (author)