Werner, Alfred coordination theory

Noyes himself had been a student of Ostwald. Lewis had spent the academic year 190001 at the institutes of Ostwald and Nernst. Colloquium topics at MIT in the period from roughly 1905 to 1910 included both chemical and physical topics Alfred Werner s coordination theory of valence, tautomerism, and the absolute size of atoms. 

Schwarz, Robert, Lawrence W. Bass, and Alfred Werner. The Chemistry of the Inorganic Complex Compounds An Introduction to Werner s Coordination Theory. New York Wiley, 1923. 

Alfred Werner, who prepared and characterized many coordination compounds. In 1893, at the age of 26, Werner proposed what is now commonly referred to as Werner s coordination theory. 

Transition metals have a distinct tendency to form complex ions (see p. 749). A coordination compound typically consists of a complex ion and counter ion. [Note that some coordination compounds such as Fe(CO)5 do not contain complex ions.] Our understanding of the nature of coordination compounds stems from the classic work of Alfred Werner, who prepared and characterized many coordination compounds. In 1893, at the age of 26, Werner proposed what is now commonly referred to as Werner s coordination theory. 

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. 

Claus s close parallel between metal hydrates and metal-ammines was attacked on the grounds that many hydrates were known for which corresponding ammines were unknown. As we shall see shortly, all of Qaus s three postulates reappeared in modified form almost four decades later in Alfred Werner s coordination theory. 

But Kekuld s stability criterion, or to be more accurate, instability criterion failed completely in the case of many coordination compounds, especially the metal-ammines, which were classified as molecular compounds by sheer dint of necessity even though they were extremely resistant to heat and chemical reagents. For example, look at Figure 1. Although hexaamminecobalt(III) chloride contains ammonia, it neither evolves this ammonia on mild heating nor does it react with acids to form ammonium salts. Also, despite its cobalt content, addition of a base to its aqueous solution fails to precipitate hydrated cobalt(III) hydroxide. It remained for Alfred Werner to explain successfully the constitution of such compounds, but the time was not yet ripe. Before considering Werner s coordination theory, we must examine one more theory of coordination compounds, perhaps the most successful of the pre-Wemer theories, namely, the Blomstrand-J0rgensen chain theory. 

The so-called video salts (salts of the cw-[CoCl2(NH3)4] ion), which played a key role in Alfred Werner s coordination theory, were first prepared in 1907 by the Czech chemist J. V. Dubsky (1882-1946), who began his career in 1904 as one of Werner s Doktoranden in Zurich. The first attempt to resolve an octahedral complex into enantiomers is also connected with Dubsky s name. Dubsky s life and work, especially his contributions to coordination chemistry, are briefly discussed in this paper. 

Many pigments and dyes of historical interest exhibit the capability of forming Werner-type coordination complexes. The relationships between the structures and color characteristics of these colorants are reviewed in this paper, with particular attention to the work of Paul Pfeiffer, a student and long-time assistant of Alfred Werner s who did extensive work in the characterization and application of Werner s coordination theory to alizarin-related dyes. 

Sidgwick applied these ideas to coordination compounds. He noted that compounds such as the cobalt ammonates, described so ably by Alfred Werner s coordination theory, could also be classified as Lewis adducts. Equation (4.2) shows the formation of the hexaamminecobalt(III) cation from the Co " " cation and six... 

A systematic investigation of structure and bonding in coordination chemistry began with the inquisitiveness of Tassaert (1798), which was extended by distinguished chemists like Wilhelm Blomstrand, Jorgensen and Alfred Werner [1] until the end of the nineteenth century. In the events, Werner s coordination theory (1893) became the base of the modem coordination chemistry. It is worth noting that the electron was discovered subsequent to Werner s theory. 

G. B. Kauffman, Alfred Werner Founder of Coordination Theory, Springer, Berlin, 1966, 127 fp. G. B. Kauffman (ed.) Coordination Chemistry A Century of Progress, ACS Symposium Series 565, Washington DC, 1994, 464 pp. 

Quoted, without citation, in Russell, "Specialism and Its Hazards," 11. To explain the combination of apparently saturated molecules, Alfred Werner introduced the theory of "coordination number" to supersede the old idea of "molecular compounds." Werner intended his theory to apply equally to organic and inorganic chemistry. Ibid., 15, 17. 

The fact that selective binding must involve attraction or mutual affinity between host and guest. This is, in effect, a generalisation of Alfred Werner s 1893 theory of coordination chemistry, in which metal ions are coordinated by a regular polyhedron of ligands binding by dative bonds. 

Photochemistry as a science is quite young we only need to go back less than one century to find its early pioneer [1], The concept of coordination compound is also relatively young it was established in 1892, when Alfred Werner conceived his theory of metal complexes [2]. Since then, the terms coordination compound and metal complex have been used as synonyms, even if in the last 30 years, coordination chemistry has extended its scope to the binding of all kinds of substrates [3,4],... 

Fig. 2.18 Alfred Werner (1866-1919) is usually described as the founder of coordination chemistry. Werner did his Ph.D. in 1889 with Professor Arthur Hantzsch and, after spending one semester with Marcellin Berthelot at the College de France at Paris, returned to the ETH at Zurich to finish his Habilitation in 1892. One year later, he became Associate Professor at the University of Zurich and was promoted as Professor of Chemistry in 1895. Remarkably, despite the widespread attention for his groundbreaking coordination theory, he was not permitted to give the basic lecture in inorganic chemistry before 1902. Werner attracted students from all over the world, supervised 230 Ph.D. theses and was the first Swiss to receive the Nobel Prize for Chemistry in 1913. In his famous book Valence and the Structure of Atoms and Molecules , published in 1923, Gilbert N. Lewis wrote ...in attempting to clarify the fundamental ideas of valence, there is no work to which I feel so much personal indebtedness as to this of Werner s (photo from Helv. Chim. Acta 75, 21-61 (1992) reproduced with permission of Dr. Kisaktirek, Editor of Helvetica Chimica Acta)...

T he major purpose of this paper is to trace the development of nomen-clature practices in the broad area of coordination compounds from the near chaos before the enunciation of the coordination theory by Alfred Werner to the present day. A secondary purpose of this paper is to give an insight into the manner in which nomenclature principles develop and become standard practice. It will be shown how, once a sound basis for a system of nomenclature was enunciated, it has been possible to modify and extend practices to cover a rapidly expanding field of knowledge. 

A t the time of Alfred Werner s birth, the only lanthanide elements that had been identified positively were lanthanum and cerium. Yttrium, a lanthanide element by all criteria except electronic configuration, was known also. However, in 1891 when Werner proposed the substance of the coordination theory, all of the elements of the lanthanide series except promethium, europium, and lutetium had been clearly identified and quite well characterized. Only promethium remained undiscovered at the time of Werner s demise. 

The coordination theory was promoted by the Swiss chemist Alfred Werner (1866-1919) in 1891. He became a professor in Zurich in 1893, and in 1913, he received the Nobel Prize in Chemistry for his investigations of complex compounds. Werner found many non-organic compounds with asymmetrical molecules that were also optically active in solutions. Such complex compounds include Co, Cr, and Fe. 

As new complex ions were synthesized, several bonding theories were postulated and rejected. The two most convincing theories, the Blomstrand-Jorgensen chain theory and coordination theory proposed by Alfred Werner, were debated extensively (a subject taken up in detail in Chapter 2) and it was coordination theory that eventually proved to be correct, winning Wemer the Nobel Prize in 1913. 

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