The populations of different TiCl4 species were analyzed for various compositions (Figure ). In general, TiCl4 species chemisorbed on MgCl2 surfaces can be classified into mononuclear species on {110}, and mononuclear and dinuclear species on {100}. Among these, the mononuclear species on {110} can be further distinguished according to the absence/presence of stereo-controlling ligands at the neighboring cationic sites within the three-site model: