The effect of dissociation of the invading electrolyte on the formation of Liesegang bands is investigated. We find, using organic compounds with known dissociation constants, that the spacing coefficient, 1 + p, that characterizes the position of the nth band as x(n) similar to (1 + p)(n) decreases with increasing dissociation constant, K-d. Theoretical arguments are developed to explain these experimental findings and to calculate explicitly the K-d dependence of 1 + p.