A thorough ab initio investigation of the pseudorotation of the pentacoordinated silicon anions SiHs...Xn- (X = F, Cl; n = 0-5) is reported. The minima and maxima of each of the systems under consideration are characterized and intrinsic reaction coordinate (IRC) calculations are performed to connect the maxima with corresponding minima. These systems are compared to the Berry pseudorotation mechanism and earlier calculations on these systems.