Sophus Mads Jørgensen 

(1837-1914) was one of the chemists who essentially contributed to the develpment of coordination chemistry 100 years ago. He was a very skillful and hard working experimentalist and synthesised and analysed a great number of different compounds with d-block metal ions. They were more complex than simple salts and belong to the class of componds which we know as coordination compounds.
His imagination about the structure of these compounds which don't obey the classical valence rules - he knew their stoichiometry - was expressed in the so-called "chain"-theory. His scientific discussions with the younger Swiss chemist Alfred Werner (1866-1919) about the structure of the coordination compounds lead to the present understanding of the principles of the structure, formulated by Werner .
Werner's work was acknowledged by the Nobel prize in chemistry in 1913 (see also http://www.almaz.com/nobel/chemistry/1913a.html
(short note 10.99).