Resonance electronic structures

So far only a start has been made (mainly by G. E. K. Branch and G. Schwarzenbach) on the problem of correlating the acidity or basicity of a substance with its resonating electronic structure. It should be possible to develop the theory of molecular structure to such an extent as to permit the reliable prediction of the behavior of substances with respect to this property and other physical and chemical properties. 

Amino-acids, Peptides, and Proteins Carbohydrate Chemistry Catalysis Colloid Science Electrochemistry Electron Spin Resonance Electronic Structure and Magnetism of Inorganic Compounds Environmentai Chemistry Generai and Synthetic Methods Heterocyciic Chemistry inorganic Biochemistry Macromoiecuiar Chemistry Mass Spectrometry Nuciear Magnetic Resonance Organic Compounds of Suiphur,... 

N.A. Piangos, C.A. Nicolaides, Weakly bound resonances Electronic structure and partial decay widths of a new He triply excited resonance, J. Phys. B 34 (2001) L633. 

Write the resonating electronic structures for the nitrate ion, NOs" the nitrite ion NO2" carbon dioxide, CO2 carbon disulfide, CS2 nitrous oxide, N2O. What shapes do these molecules have and what are the expected values of the bond angles Note that there are three valence-bond structures possible for CO2 that give each atom an argononic structure. 

Chemical Physics of Solids and Their Surfaces Colloid Science Electrochemistry Electron Spin Resonance Electronic Structure and Magnetism of Inorganic Compounds... 

The surface work fiincdon is fonnally defined as the minimum energy needed m order to remove an electron from a solid. It is often described as being the difference in energy between the Fenni level and the vacuum level of a solid. The work ftmction is a sensitive measure of the surface electronic structure, and can be measured in a number of ways, as described in section B 1.26.4. Many processes, such as catalytic surface reactions or resonant charge transfer between ions and surfaces, are critically dependent on the work ftmction. 

Venanzi T J 1982 Nuclear magnetic resonance coupling constants and electronic structure in molecules J. Chem. Educ. 59 144-8... 

Write a resonance form for guanine in which the six membered ring has an electronic structure analogous to benzene Show all unshared pairs... 

The electronic structure of nitrile A-oxides may be represented as a resonance hybrid of the canonical structures (335a-e). The structure (335a) is commonly used to represent this reactive species. 

Compare electrostatic potential maps of enolates derived from 2-butanone, 4,4-dimethyl-2-pentanone, 4,4,4-trifluoro-2-butanone and l-phenyl-2-propanone with those of acetone. Which substituents cause significant changes in the electronic structure of these enolates and what are the nature of these changes Justify your answers by making drawings of any important resonance contributors. 

Examine the geometry of the most stable radical. Is the bonding in the aromatic ring fuUy delocalized (compare to model alpha-tocopherol), or is it localized Also, examine the spin density surface of the most stable radical. Is the unpaired electron localized on the carbon (oxygen) where bond cleavage occurred, or is it delocalized Draw all of the resonance contributors necessary for a full description of the radical s geometry and electronic structure. 

Quadrupole coupling constants for molecules are usually determined from the hyperfine structure of pure rotational spectra or from electric-beam and magnetic-beam resonance spectroscopies. Nuclear magnetic resonance, electron spin resonance and Mossbauer spectroscopies are also routes to the property. There is a large amount of experimental data for and halogen-substituted molecules. Less data is available for deuterium because the nuclear quadrupole is small. 

Among the other physicochemical studies mention should be made of the determination of the electron structure and energy of resonance carried out for a number of the principal 8-aza analogs, and of the determination of the dissociation constants and crystal structure. ... 

Lewis structure An electronic structure of a molecule or ion in which electrons are shown by dashes or dots (electron pairs), 166-167,192q formal charge, 171-172 nonmetal oxides, 564-565 oxoacids, 567 resonance forms, 170-171 writing, 168-169 Libby, Willard, 174... 

Magnetic resonance methods in the study of the electronic structure of transition metal complexes. 

The Determination of the Type of Bond in Crystals. Resonance of Molecules and Crystals Among Several Electronic Structures. 

Arguments based mainly on bond energies5) and interatomic distances6) have recently led to the determination of the normal electronic structures of a number of molecules. The hydrogen halides resonate between the... 

This table has been published by L. Pauling, Pr. Nat. Acad. 18, 293. 1932, in connection with the discussion of the resonance of molecules among several electronic structures. 

Often no single electronic structure can be assigned to a molecule or complex ion, which instead resonates between two or more Lewis structures, as discussed before. An example is the carbonate ion, C Og, which assumes all three of the structures... 

Distances in Molecules and Complex Ions in Crystals Resonating between Two or More Electronic Structures. 

The second way in which the substituent R affects the charge distribution of the molecule is called the resonance effect (or sometimes the tautomeric or electromeric effect). This results when the molecule resonates among several electronic structures. For example, for aniline the structures... 

Three years ago it was pointed out2 that observed values of interatomic distances provide useful information regarding the electronic structures of molecules and especially regarding resonance between two or more valence bond structures. On the basis of the available information it was concluded that resonance between two or more structures leads to interatomic distances nearly as small Us the smallest of those for the individual structures. For example, in benzene each carbon-carbon bond resonates about equally between a single bond and a double bond (as given by the two Kekul6 structures) the observed carbon-carbon distance, 1.39 A., is much closer to the carbon-carbon double bond distance, 1.38 A., than to the shrgle bond distance, 1.54 A. 

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