INORGANIC OPTICAL-ACTIVITY

This account plaits three major inorganic threads: stereochemistry and optical activity; qualitative analysis; and aqueous coordination chemistry. Knowledge of the phenomena of optical activity has grown largely through inorganic systems, from Blot (quartz), through mineralogy (Haidinger-circular dichroism) and crystal properties (e.g., the spontaneous resolution of sodium chlorate), to the Cotton effect and the resolutions of Werner's cationic hexol and Mann's anion. The stereochemistries of oligosulfides of the platinum metals are described. [PtSx](2-) (e.g., x = 15) can be resolved through diastereo- isomeric salts with (+)-[Ru(bipy)(3)](2+). When preparations of oligosulfides of platinum are controlled carefully, the sole product is optically active (NH4)(2)[PtS17].2H(2)O. This is a unique spontaneous appearance of optical activity in an inorganic molecule.