Pauling, Linus resonance theory

I was inspired too by Linus Pauling (1901-94), another polymath with humanistic concerns. His Nature of the Chemical Bond (1939) brought a new perspective to theories of molecular structure, and refuted the implication of a popular examination question of the time, Is inorganic chemistry a largely closed and finished subject Pauling s resonance theory, formally based on the quantum-mechanical valence-bond (VB) method for... 

Linus Pauling, A Resonating-Valence-Bond Theory of Metals and Intermetallic Com-... 

Pauling, Linus. "The Nature of the Theory of Resonance." In Perspectives in Organic Chemistry. Ed. [Sir] Alexander Todd. New York Interscience Publishers, 1926. Pp. 18. 

This process of constructing functions for the various resonant formulae, followed by an adequate combination of them, is mathematically more complex than the mathematics of molecular orbital theory. It is therefore understandable that, after the initial preference of chemists for the v.b. bond theory which has a closer relation to Lewis structures - especially due to the contribution of Linus Pauling - m.o. theory became increasingly popular. In addition, m.o. theory leads directly, not only to fundamental states (through the occupied m.o.), but also to excited states (through vacant m.o.) of molecules. In recent years, however, a new form of valence-bond theory has been developed that is more amenable to computation (spin-coupled valence-bond theory) in which the molecular wavefunction is expressed as a linear combination of all the coupling schemes of the various electrons corresponding to the same resultant spin (ref. 97). 

The VB theory described molecular structure by a set of resonating structures. This did not mean that each structure in such a set would be considered as present individually, but that the sum of these would correspond to the set. The resonance theory provided merely a model, an approach, rather than a unique reflection of reality. There were proponents and opponents of the theory as is the case with most theories. George Wheland (Fig. 1.8a) published a book in 1944 about the theory of resonance [36]. Linus Pauling (Fig. 1.8b) also contributed to the theory especially... 

Linus Carl Pauling (1901-1994), American physicist and chemist, in the years 1931-1964 professor at the Calitbmia Institute of Technology in Pasadena, in 1967-1969 professor at the University of California, San Diego, from 1969-1974 professor at the Starrfbrd University. Me received the 1954 Nobel prize for his research into the nature of the chemical bond and its application to the efucidsrSon of the structure of complex substanced". In 1962 he received the Nobel peace prize. His major achievements are the development of fhe fhe-ory of chemical bond, i.a., the VB method (also called resonance theory), and determining fhe... 

This model is very familiar to chemists in its semi-intuitive qualitative extension known as resonance theory, which was first proposed by Linus Pauling in his work... 

Heterocyclic systems have played an important role in this historical development. In addition to pyridine and thiophene mentioned earlier, a third heterocyclic system with one heteroatom played a crucial part protonation and methylation of 4//-pyrone were found by J. N. Collie and T. Tickle in 1899 to occur at the exocyclic oxygen atom and not at the oxygen heteroatom, giving a first hint for the jr-electron sextet theory based on the these arguments.36 Therefore, F. Arndt, who proposed in 1924 a mesomeric structure for 4//-pyrone, should also be considered among the pioneers who contributed to the theory of the aromatic sextet.37 These ideas were later refined by Linus Pauling, whose valence bond theory (and the electronegativity, resonance and hybridization concepts) led to results similar to Hiickel s molecular orbital theory.38... 

The contributions of Erich Hiickel to the development of molecular orbital theory have already been mentioned in the subsection on Germany (Section 5.4.1) the development of semi-empirical quantum mechanical treatments in organic chemistry by M. J. S. Dewar has been discussed in Section 5.5. In the early development of the application of quantum mechanics to chemistry, Linus Pauling (1901-1994)359 was pre-eminent. He was associated with CalTech for most of his career. His work before World War II generated two influential books the Introduction to Quantum Mechanics (with E. Bright Wilson, 1935)360 and The Nature of the Chemical Bond (1939).361 He favoured the valence-bond treatment and the theory of resonance. 

A review of the unsynchronized-resonating-covalent-bond theory of metals in presented. Key concepts, such as unsynchronous resonance, hypoelectronic elements, buffer elements, and hyperelectronic elements, are discussed in detail. Application of the theory is discussed for such things as the atomic volume of the constituents in alloys, the structure of boron, and superconductivity. These ideas represent Linus Pauling s understanding of the nature of the chemical bond in metals, alloys, and intermetallic compounds. 

In a footnote to his 1949 paper entitled A Resonating-Valence-Bond Theory of Metals and Intermetallic Compounds, Linus Pauling gave an example of a simple statistical treatment to derive the metallic orbital [27]. Nevertheless, it took him three and one-half decades to publish the detailed statistical treatment [34-36], which is given in the following. 

Sir Christopher Keik Ingold (1893-1970) was bom in IHord, England, and received his D.Sc. at the University of London. He spent most of his career at University College, London (1930-1961), where he published over 400 scientific papers. Along with linus Pauling, he was instrumental in developing the theory of resonance. 

The VB method was developed by Linus Pauling with the name of theory of resonance. 

The nature of the chemical bond. Application of results obtained from the quantum mechanics and from a theory of paramagnetic susceptibility to the structure of molecules. J. Am. Chem. Soc. 53 (1931) 1367—1400. SP 5 The nature of the chemical bond. II. The one-electron bond and the three-electron bond. J. Am. Chem. Soc. 53 (1931) 3225—3237. SP 6 Interatomic distances in covalent molecules and resonance between two or more Lewis electronic structures. Proc. Natl. Acad. Sci. 18 (1932) 293—297. The additivity of the energies of normal covalent bonds. Proc. Natl. Acad. Sci. 18 (1932) 414-416. (Linus Pauling and Don M. Yost). 

The discussion of tetragonal boron by the resonating-valence-bond theory of electron-deficient substances. Z. Kristall. 112 (1959) 472—478. (Linus Pauling and Barclay Kamb). 

Recent advances in the unsynchronized-resonating-covalent-bond theory of metals, alloys, and intermetallic compounds and its apphcation to the investigation of structures and properties of such systems. In Modelling of Structure and Properties of Molecules, Z. B. Maksic, ed., Ellis Horwood Ltd., Chichester, England, (1987), pp. 5-37. (Linus Pauling and Zelek S. Herman). 

The unsynchronized-resonating-covalent-bond theory of the structure and properties of boron and the boranes. In Advances In Boron and the Boranes (Molecular Structure and Energetics, Vol. 5), Joel F. Liebman, Arthur Greenberg, and Robert F. Williams, eds., VCH Publishers, New York, (1988), pp. 517-529. (Linus Pauling and Zelek S. Herman). 

The theory of resonance was developed by Linus Pauling in the 1930s. According to this theory, many molecules and ions are best described by writing two or more Lewis structures and considering the real molecule or ion to be a composite of these structures. We call... 

This discovery was to be the beginning of the use of exchange terms in the quantum mechanics of atoms and molecules. It became the key factor that shortly afterward allowed Walter Heitler and Fritz London to obtain the first successful quantum mechanical calculation of the covalent bond in the simplest case of a diatomic hydrogen molecule. Exchange terms would also pave the way for the notion of quantum mechanical resonance and the development of the quantum mechanical theories of bonding by Linus Pauling and many others. ... 

---