The Phenomenon of Conglomerate Crystallization. XVII. Clavic Dissymmetry in Coordination Compounds. XV. The Effect of the Charge Compensating Ions on the Phenomenon of Conglomerate Crystallization

Abstract

Abstract In this report, we discuss the effect of the counter ion on the crystallization behaviour of chiral ions which may produce racemic or conglomerate crystals. We demonstrate that the counter ion is often capable of influencing the crystallization pathway and provide examples of substances in which the same chiral ion produces enantiomorphic crystals or racemic crystals depending on the nature of the counter ion. Moreover, we demonstrate that the crystal structures of such species amply demonstrate the reasons for such differences in crystallization pathway. In the species selected for the illustrations, the underlying phenomenon being influenced by the choice of counter ion is hydrogen bonding. This summary provides examples of counter ion pairs as varied as halides vs NO3 −, halides vs NO2 −, K+1 vs Ag+, etc., influencing the choice of crystallization pathway. Also, we illustrate the fact that the same ion (i.e., NO3 −) can play either a positive or a negative role in such a selection.