Bond electron density

Consider the repulsive effects of the d electrons in a series of MLe complexes as the d configuration of the central metal varies across the transition-metal series. All d electron density will repel the bonding electron density. The effects on the 2g eleetron density will be relatively small, however, as these orbitals largely lie inbetween the bonding regions. On the other hand, electron density directly frustrates the bonding. 

Severai common poi /atomic oxoanions, inciuding suifate, perchiorate, and phosphate, have inner atoms from the third row of the periodic tabie. In these anions, vaience d orbitais are avaiiable to participate in bonding. Figure 10-47 shows how a n orbitai can form through side-by-side overiap of a d orbital on one atom with a.7, p orbital on another atom. As with other itt bonds, electron density is concentrated above and below the bond axis. 

When a ligand is more electronegative than the central atom, it draws the bonding electron density away from the central atom so that the space occupied by the bonding domain in the valence shell of the central atom decreases with increasing difference of electronegativity... 

A high electron density surface (also called a bond electron density surface) shows the core of electron density around each atomic nucleus and regions where neighboring atoms share electrons (covalent bonding regions). 

In modem usage, a Lewis acid would be defined as any substance capable of accepting electron density and a Lewis base as any substance capable of donating electron density. Many substances are capable of being either one or the other and some materials e.g., H2O) are capable of being both. A Lewis acid-base interaction requires coordination of the two so that the bonding electron density is shared by both the acid (acceptor) and the base (donor). With this definition, it becomes difficult... 

The first examples of nitrofluorination of alkenes were demonstrated by the reaction in a solution of 10% nitric acid in hydrogen fluoride at — 10 C.204 Further investigation has shown that the rate of this conjugate addition is determined predominantly by the nature of the tr-bond (electron density, polarity).205 As a rule, the reaction is carried out at temperatures between - 60 C (i.e., 1,1-dichloro-or 1,1-difluoroethene) and + 20 C. However, nitrofluorination of hexafluoropropene is only successful at higher pressure and temperature, i.e. if the alkene rc-bond is less polar the regioselectivity of the addition is also unsatisfactory,205 e.g. reaction of 1 and 2.206... 

The Karplus Relationship and the Correlation of Two Anomalous 13C-Vicinal H Coupling Constants with Bonding Electron Density Distribution Found by Accurate X-Ray Analysis, L. T. J. Delbaere, M. N. G. James, and R. U. Lemieux, J. Am. Chem. Soc., 95 (1973) 7866-7868. 

Reduced Jew 13C NMR coupling constant (which is related to the C—H c-bonding electron density). 

Answer Abond will shorten (lengthen) if bonding electron density increases (decreases) and/or antibonding electron density decreases (increases) between the extremities. If... 

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