Reactions of [RuCl2(eta(6)-arene)(2) (arene = benzene, p-cymene) with nido-[7-R-10-L-7,8-C2B9H9](-) in THF at room temperature for 3 d give the (arene)ruthenacarborane complexes closo-[3-Ru(eta(6)-arene)-l-R-8-L-l,2-C2B9H9](-) {arene = benzene, R = H [L = Me2S (1a), THT (1b), EtPhS (1c)], R = Me [L = Me2S (2a)]; arene = p-cymene, R = H [L = Me2S (3a)]} and mercaptan closo-[3-Ru(n(6)-arene)-1-R-8-HS-1,2-C2B9H9] [arene = benzene, R = H (4), Me (5); arene = p-cymene, R = H (6)] in yields of 20-40% and 22-29%, respectively. The asymmetric ligand nido-[9-Me2S-7,8-C2B9H10](-) leads to the thioether complex closo-[3-Ru(q 6 -benzene) -7-MeS- 1,2C(2)B(9)H(10)] (8) in 34 % yield under the same reaction conditions. The crystal structure of la is described and compared with those of 4 and 8. The fully assigned B-11 NMR spectroscopic data for a whole series of ruthenacarboranes having B-substituted sulfonium, thioether and mercaptan groups are presented. These data show a relation between antipodal cluster atom distances (antipodal distance) and antipodal effect (AE) in the crystal structures of these complexes and for other families of heteroboranes such as closo-[EB11H11] and closo-[EB9H9].