Nuclear magnetic resonance and infrared spectra have been obtained for CH,TiCI,, (CH,),TiCI,, and some related materials. The rather unusual n.m.r. data for these compounds and for C2H5TiC1, are compared with the results for related species involving Group IVA elements and the variations are discussed in terms of n.m.r. and bonding parameters. Exchange of methyl groups between CH,TiCl, and (CH,),TiCI, and between each of these compounds and (CH,),Zn has been studied by this means. Infrared data remain difficult to interpret, and unambiguous assignment of bands has not been achieved.Les spectres r.m.n. et infrarouges de CH,TiCI,, (CH3),TiC1, et de quelques substances apparentees, ont bte obtenues. Les donnCes r.m.n. inhabituelles obtenues pour ces composks et pour C,H5TiCI, sont compartes avec les rbsultats obtenus pour des espkces apparentbes impliquant les elements du groupe IVa; les variations observees sont discutkes en termes de paramttres de liaison et r.m.n. L'bchange des groupes mCthyles entre CH,TiCI, et (CH,),TiCI, et entre chacun de ces composks et (CH,),Zn, a btb btudii. par ces moyens. Les donntes infrarouges demeurent difficiles a interpreter et une attribution dbfinitive des bandes n'a pas kt15 effectuee.