Werners theory

Whereas Kekule disposed of complex compounds by banishing them to the limbo of molecular compounds , other chemists developed highly elaborate theories to explain their constitution and properties. The most successful and widely accepted of such pre-Werner theories was the chain theory,47 advanced by Christian Wilhelm Blomstrand (1826-1897)4 and developed by Sophus Mads Jorgensen (1837—1914).46 49 50 Although Werner s ideas eventually triumphed, this did not invalidate Jorgensen s observations. On the contrary, his experiments have proven completely reliable and provided the experimental foundation not only for the Blomstrand—Jorgensen chain theory but also for Werner s coordination theory. 

These authors apply Werners Theory to deduce that the olose association is here... 

The Werner theory of coordination compounds was based on a group of compounds that is relatively slow to react in solution and thus easier to study. For this reason, many of his examples were compounds of Co(III), Rh(III), Cr(III), Pt(II), and Pt(IV), which are kinetically inert or slow to react Examination of more reactive compounds over the years has confirmed their similarity to those originally smdied, so we will include examples of both types of compounds in the descriptions that follow. 

Frankland, just one year later, noted that the saturation capacity" of an element cannot be exceeded 17). We will return to this point in our discussion of the Werner theories. 

In a lecture in 1848 Louis Pasteur considered for the first time some of the chemical problems involved with stereochemical compounds (41) This was an area of discussion which had deep implications in the Werner theory, yet to come. 

With the discovery of x-ray diffraction and the opportunity this gave to determine exactly where the atoms are in a crystal, there arose an unexpectedly direct way to ascertain the measure of reality behind the Werner theory and its implied equivalence of some primary and secondary bonds. 

Historically Important Coordination Compounds Some Pre-Werner Theories of Coordination Compounds... 

In this broad chronological survey, some of the most historically significant coordination compounds are first discussed, along with several pre-Werner theories of their formation and constitution, followed by Werner s theory and his most important discoveries. This article concludes with a brief consideration of discoveries and developments from Werner s time through 2003. ... 

A very significant point arises with the next member of the series, C0CI3 3NH3. Werner s theory requires that it be represented as structure Vlll and formulated as [CoCl3(NH3)3]. The Werner theory predicted that the complex... 

The supersession of the most successful pre-Werner theory of the structure of coordination compounds, the so-called Blomstrand-J0rgensen chain theory, by Alfred Werner s coordination theory constitutes a valuable case study in scientiffc method and the history of chemistry. The highlights of the Werner-J0rgensen controversy and its implications for modem theories of chemical structure are Wretched in this article. 

J0rgensen immediately seized upon such so-called discrepancies in an attempt to discredit their results. But in its explanation of anionic complexes and its demonstration of the existence of a continuous transition series (Obergangsreihe) between metal-ammines (MA ) and double salts the Werner theory succeeded in an area in which the Blomstrand-J0rgensen theory could not pretend to compete. 

Direct confirmation of the octahedral configuration of the [PtCl J ion was obtained two years after Werner s death by R. W. G. Wyckoff from X-ray diffraction studies on the ammonium salt. As Wyckoff said, A more complete agreement with the predictions of the Werner theory could scarcely have been imagined . Werner had also deduced that the four-coordinate platinum(ll) complexes have a square planar configuration, and this was also soon verified by the same technique. 

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