Wilkinson's catalyst in [RhCl(PPh3)3], redviolet in colour and has square planar structure. It is used for selective hydrogenation of organic molecules at room temperature and pressure. TiCl4+(C2H5)3Al is ZeiglerNatta catalyst. (C2H5)4Pb is an anti-knocking agent. cis-platin is used as an anti-cancer agent.