Five complexes of cadmium(II) containing an Fe → Cd donor-acceptor bond have been synthesized from the reaction of a neutral organometallic tridentate ligand trans-(CO) 3Fe(Ph 2Ppym) 2 (Ph 2Ppym = 2-(diphenylphosphino)pyrimidine) with various cadmium(II) salts and fully characterized by single-crystal X-ray analysis: [(CO) 3Fe( μ-Ph 2Ppym) 2CdCl 2] 2·0.5CHCl 3· 2.5thf ( 1) belongs to space group P1¯ with a = 12.311(4), b = 17.083(2), c = 21.994(12) Å, α = 103.34(2), β = 92.42(5), γ = 101.07(1)° and Z = 2; [(CO) 3Fe( μPh 2Ppym) 2CdBr 2]·2CH 2Cl 2 ( 2) to space group C2/ c with a = 25.691(1), b = 19.953(1), c = 8.584(1) Å, β = 102.14(1)° and Z = 4; [(CO) 3Fe( μ-Ph 2Ppym) 2Cdl 2], 3, space group P2 l/ n with a = 13.811(1), b = 14.019(1), c = 19.738(1) Å, β = 102.26(1)° and Z = 4; [(CO) 3Fe( μ-Ph 2Ppym) 2Cd(NCS) 2]·2CH 2Cl 2 ( 4) to space group P1¯ with a = 9.986(1), b = 12.014(1), c = 20.501(1) Å, α = 98.10(1), β = 91.78(1), γ = 112.07(1)° and Z = 2; [(CO) 3Fe( μ-Ph 2Ppym) 2Cd(CH 3CN)(H 2O)]·2ClO 4·1.5CHCl 3 ( 5) to space group P1¯ with a = 12.063(2), b = 12.922(2), c = 17.502(3) Å, a = 75.61(1), β = 71.14(1), γ = 79.12(1)° and Z = 2. In this series of complexes, the Fe-Cd distance lies between 2.651(2) and 2.818(1) Å which is indicative of the existence of donor-acceptor metal-metal bonding. Although the different halides have no significant influence on the Fe-Cd bond distance, the SCN − group does shorten the Fe-Cd distance owing to its delocalized electronic structure in 4. Furthermore, in the [(CO) 3Fe( μ-Ph 2Ppym) 2Cd(MeCN)(H 2O)] 2+ cation of complex 5, the dative Fe → Cd bond distance, being comparable with the covalent Fe-Cd bond distance in related heterobimetallic compounds, is mainly determined by the electronic characteristics of this bond rather than the restriction imposed by the rigid bridging ligand.