Coordination
Compounds
Alfred Werner (1866-1919), a Swiss chemist was the first to formulate
his ideas about the structures of coordination compounds He prepared
and characterised a large number of coordination compounds and
studied their physical and chemical behaviour by simple experimental
techniques Werner proposed the concept of a primary valence and
a secondary valence for a metal ion Binary compounds such as
CrCl3, CoCl2 or PdCl2 have primary valence of 3, 2 and 2 respectively