The X-my crystal structure analyses of the three redoX pairs [Rh2(CO)2LL’{mu-PhNC(Me)NPh}2]z [z = 0, 1; L = L’ = PPh3 (1, 1+); L - L’ = P(OPh)3 (2, 2+); L = PPh3, L’ - P(OPh)3 (3, 3+)] are reported and the molecular structures compared with those Of [Rh2(CO)2(PPh3)2(mu-RNNNR)2]z [z - 0, 1; R = p-tolyl (4,4+)]. These have locally planar rhodium coordination with the planes splayed apart between 20 and 40-degrees. The, non Rh...Rh distance of ca. 2.9 angstrom in the neutral complexes is reduced by between 0.14(2) and 0.262(4) angstrom on oxidation. These and other changes in the molecular structure arc consistent with the HOMO of the neutral complexes being delocalized, over the two metals, and having rhodium-rhodium sigma* character. ESR spectroscopic analysis is reported on 1+-4+ and on the related ligand-bridged [Rh2]3+ species [Rh2(CO)2(mu-dPPM)(mu-RNNR)2]+ [R = p-tolyl (5+)], [Rh2(mu-diMen)2(mu-dppM)2]3+ (6+, dimen = 1,8-diisocyanomenthane), [Rh2(mu-TM4)2(mu-dppM)2]3+ [TM4 = 2,5-diisocyano-2,5-dimethylhexane (7+)], [Rh2(mu-CNCH2CH2CH2NC)2(mu-dppm)2]3+ (8+), [Rh2(mu-HTP5)2(mu-dppm)2]3+ (9+,HTP5 - 1,5-diisocyano-1,1,5-triphenylpentane), [Rh2(CO)2(PMe2Ph)2(mu-chp)2]+(10+), [Rh2(mu-mhp)2(COD)2]+ (11+). [Rh2(mu-ChP)2(NBD)2]+ (12+), and [Rh2(mu-mhp)2(NBD)2]+ (13+). The spectroscoPiC parameters are shown to be dependent on the geometry of the cations and especially on the splay angle between the rhodium coordination planes. Quantitative interpretation of the ESR parameters suggests an orbital composition for the SOMO which is in good agreement with extended Huckel MO calculations on the model compounds [{Rh(H)2(CO)2}2]2- (14) and [Rh2(CO)4(mu-HNNNH)2] (15). The theoretical and ESR analyses are in full accord with the X-ray results and together provide a coherent picture of the electronic and geometric structures of ligand-bridged [Rh2]3+ complexes.