AlCl₃ is added in small quantities along with TiCl₄ to industrial reactors during the combustion synthesis of titanium dioxide nanoparticles in order to promote the rutile crystal phase. Despite the importance of this process a detailed mechanism including AlCl₃ is still not available. This work presents the thermochemistry of many of the intermediates in the early stages of the mechanism, computed using quantum chemistry. The enthalpies of formation and thermochemical data for AlCl, AlO, AlOCl, AlOCl₂, AlOCl₅Ti, AlO₂, AlO₂Cl, AlO₂Cl₂, AlO2Cl₃Ti, AlO₃Cl₂Ti, Al₂Cl₆, Al₂O₂Cl, Al₂O₂Cl₃, Al₂O₃, and Al₂O₃Cl₂ were calculated using density functional theory (DFT). A full comparison between a number of ab initio methods is made for one of the important species, AlOCl, in order to validate the use of DFT and gauge the magnitude of errors involved with this method. Finally, equilibrium calculations are performed to try to identify which intermediates are
likely to be most prevalent in the high temperature
industrial process, and as a first attempt to
characterize the nucleation process.