A simple model for collision-induced dissociation processes in the systems MX + A is proposed where A, M, and X denote a chemically inert projectile atom, an alkali atom, and a halogen atom, respectively. This model is based on the kinematic analysis of the reaction and considers the formation of atomic ions M(+) and X(-) and ionic complexes MA(+) and MX(-) from a unified viewpoint. The model describes qualitatively correctly almost all the features of the ionic complex formation observed experimentally.