OXYGEN-BRIDGED ADDUCTS FORMED BY CHEMICAL-REACTIONS OF SOLID ALUMINUMHALIDES - EXPERIMENTAL DILEMMA AND AB-INITIO CALCULATIONS OF HETERODIMER COMPLEXES ALX(3)-Y (X=F, CL, Y=OH-, H2O)

Starting from new experimental facts given by ESR, MS, and other physi cal and chemical methods, the role of bridged intermediates in the for mation of catalytic active solids by thermal chemical reactions includ ing the gaseous phase is discussed. Structures of oxygen-bridged adduc ts of AlF3 and AlCl3 with OH- and H2O have been explored at the HF and MP2 levels using 6-31G, 6-31+G*, and 6-311G** basis sets, The reacti on enthalpies of complex formation are calculated for several temperat ures. Both hydroxyl and water complexes were found to be energetically stable complexes that have a real chance to take part in high-tempera ture heterogeneous reactions like the formation of activated aluminum halide catalysts.