Tin(II) xanthates form adducts with donor molecules and react with excess xanthate to form the tris-xanthato ion, Sn(EtOCS2)3-. No such reactions are observed with tin(IV) xanthates. Reaction of quinolin-8-ol with tin(IV) ethylxanthate results in the replacement of two xanthate moieties by two oxinato ions. The crystal structure of [Sn(EtOCS2)4] has been determined by single-crystal X-ray diffraction at 295 K and refined by least squares to a residual of 0·038 for 2378 ‘observed’ reflections. The tin(IV) coordination environment resembles that observed in the N, N-diethyldithiocarbamate analogue, two of the xanthate ligands being monodentate and coordinating cis [Sn-S, 2·488(2), 2·499(2) Å] in the six-coordinate coordination sphere while the other two ligands are bidentate, the Sn-S distances trans to the monodentate ligands being slightly longer [2·617(2), 2·627(2) Å] than the other two [2·562(2), 2·539(2)Å]. Crystals are monoclinic, P21/c, a 10·341(5), b 10·465(4), c 21·88(1) Å, p 98·36(4)°, Z 4.