(C 6F 5) 3Sb has been found to react with interhalogens and halo-pseudohalogens, IX(X = Cl, Br, N 3 and NCO), pseudohalogen (SCN), and elemental sulphur to give oxidative addition products ( I–VI). (C 6F 5) 3SbS( VI) may also be prepared by the reaction of (C 6F 5) 3SbCl 2 with H 2S. Metathetical reactions of (C 6F 5) 3SbCl 2 with appropriate metallic salts yield covalent pentacoordinate disubstituted products ( V, VII–XII) of the general formula, (C 6F 5) 3SbY 2 (Y = NCS, NCO, −ONCMe 2, −ONCMePh −NCO(CH 2) 2C O and p-NO 2C 6H 4OCO). Treatment of (C 6F 5) 3SbCl 2 with aqueous NaN 3 gives the binuclear oxo-bridge compound, [(C 6F 5) 3SbOSb(C 6F 5) 3](N 3) 2·( III) and ( IV) are also accessible by displacement reaction of ( I) or ( II) with the corresponding metallic salt. Molecular weight, conductance measurements, and IR spectra on the new organoantimony(V) derivatives have been obtained. Reductive cleavage reactions of (C 6F 5) 3SbS with hexaaryldileads, Ar 6Pb 2(Ar = Phenyl, p-tolyl) produce (C 6F 5) 3Sb and the corresponding bis(triaryllead) sulphide but treatment of (C 6F 5) 3SbX 2(X = NCO, Cl) with Ar 6Pb 2 gave Ar 4Pb and Ar 2PbX 2 together with (C 6F 5) 3Sb. (C 6F 5) 3SbCl 2 and bis(triorganotin)sulphides undergo exchange of anionic groups.