From his experience in organic chemistry, in which the valence of carbon always is 4, Kekulé held that the valance of an element is constant. To maintain a constant valence, Kekulé conceived of "molecular compounds"--dualistic combinations of two compounds. For instance, Co(NH3)6Cl3 would be written as CoCl3·6NH3.
|
|
The coordination theory is an abrupt break with both the Kekulé valence theory and the Blomstrand- Jørgensen chain theory. It assumes that the metal is bound to 6 atoms or groups, creating a radical. The remaining atoms or groups are loosely bound to this radical. To give you a little practice, I would like you to work on the structure of a typical metal ammine, Co(NH3)6Cl3 which we call "luteo" cobalt chloride. |
 |
|
Alfred Werner
(1866 - 1919) |