The spontaneous and photolytically induced reactions of AIF and AICI in the presence of HCI and HBr in solid argon matrices were followed and the products identified and characterized by means of IR spectroscopy. Quantum mechanical calculations allow for a further evaluation of the properties of the reaction products. These are the adducts AIF.HCI, AIF.HBr, and AICI.HBr, representing the products of spontaneous reactions, and the trivalent Al(III) hydrides HAIFCI, HAIFBr, and HAICIBr, which were formed upon photoactivation of these complexes. All three hydrides are planar molecules (C-s symmetry) with bond angles in agreement with the predictions of the VSEPR theory. In addition, the mixed halides AIFCl(2), AIFBr(2), and AICIBr(2) were formed upon photolysis. The bisadducts AIF.(HCI)(2) and AIF.(HBr)(2) are likely to be the precursors to these species.