Theory of Coordination: Blomstrand-Jorgensen Chain Theory In 1850-1870 problems p ose about how the structure of complex compounds. At that time organic chemists found that carbon atoms always have a valence of four and organic compounds have a chain structure. For example: CH 3 (CH 2 ) 3 Cl structure CH 3 -CH 2 -CH 2 -CH 2 -C l. Based on this, Blomstrand (Sweden, 1869) proposed a chain theory for complex metal structures. Because each element has a fixed valence, Blomstrand and Jorgensen state that in the cobalt (III) complex there are only three bonds. The Chain Theory proposed by Blomstarnd-Jorgensen is one of the main efforts to explain the bonds formed in complex compounds. Blomstrand and Jorgensen proposed his theory based on the reaction of the formation of AgCl in the complex compound CoCl 3 . x NH 3 using silver nitrate reagent. CoCl 3 . 6 NH 3 (yellow orange) + AgNO 3 (excess) → 3 AgCl CoCl 3 . 5 NH 3 (pink) ...