Cobalt ammonia

Metal salts in alkaline solution Cuprammonium complex Nickel and cobalt ammonia complex Cyanides (q.v.) Copper pyrophosphates Plumbites Zincates... 

The seminal studies on these complex compounds were conducted by Alfred Werner in an intensive period of work at the turn of the century. A typical example of the problems that Werner addressed lies in the various compounds which can be obtained containing cobalt, ammonia and chlorine. Stable and chemically distinct materials with formulations Co(NH3) Cl3 (n = 4,5 or 6) can be isolated. The concepts of valency and three-dimensional structure in carbon chemistry were being developed at that time, but it was apparent that the same rules could not apply to... 

Notes 1. Cobaitous ammonia ion is easily oxidized by air to cobaltic ammonia ion. 2. Chromic ammonia ion forms only slowly, and is decomposed by boiling, to give chromium hydroxide precipitate. 

Although Pmssian Blue, synthesized in 1704, was the first officially recognized metal coordination complex to be made, discovery of this group of transition metal complex ions is often credited to Taessert, who in 1798 prepared the first known cobalt ammonia salts. His work inspired a revolution in inorganic chemistry. At the turn of the nineteenth century, amidst the flourishing developments of organic chemistry, the striking colors... 

The discovery of the Kubas complex was a defining event in the historical development of coordination chemistry. By 1920, the Lewis ideas on the role of electron pairs in bonding had already associated the coordinate bond with the donation of a lone pair to a metal. For example, donation of the ammonia lone pair to was implicated in the classical Werner cobalt-ammonia complexes. Subsequent developments extended the coordination concept beyond lone-pair donors. Around 1950, a series of discoveries by Wilkinson, Chatt, Fischer, and others showed how the electrons of unsaturated ligands such as cyclopentadienide ion and ethylene can also bind to metal ions. These complexes stimulated the modem development of organometallic chemistry and homogeneous catalysis. 

K. Osseo-Asare, Application of activity-activity diagrams to ammonia hydrometallurgy II. The copper, nickel and cobalt ammonia water systems at elevated temperatures , Process Fundamental Considerations in Selected Hydrometallurgy Systems, M. Kuhn (Editor), AIME, New York, 1981, pp. 360-369. 

The father of modern coordination chemistry was Alfred Werner, who was born in 1866 and lived most of his life in Zurich. At the time it was known that the oxidation of cobalt(II) (cobaltous) salts made alkaline with aqueous ammonia led to the formation of cobalt(III) (cobaltic) salts containing up to six ammonia molecules per cobalt atom. These ammonia molecules were evidently strongly bonded because very extreme conditions— boiling sulfuric acid, for example—were needed to separate them from the cobalt. There had been considerable speculation about the cobalt-ammonia bonding and structures such as... 

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