Bonding environment

Are relatively transferrable in the sense that the basis for a given atom is flexible enough to be used for that atom in a variety of bonding environments (where the atom s hybridization and local polarity may vary). 

Fig.1 Most common low coordinate bonding environments for carbon and phosphorus...

The two different types of C—H bonds in ethanoi have siightiy different bond energies, because the bonding environment about one C atom differs siightiy from the bonding environment about the other C atom. 

Castro CE, RS Wade, DM Riebeth, EW Bartnicki, NO Belser (1992b) Biodehalogenation rapid metabolism of vinyl chloride by a soil Pseudmonas sp. Direct hydrolysis of a vinyl C-Cl bond. Environ Toxicol Chem 11 757-764. 

Table 4 Correlation of the number of classical structures with calculated bond lengths for Ceo and Cn. The bond environment column describes the arrangements of the carbon atoms which have the bond in common. The column labelled with a f is the bond order calculated using resonance theory as described in the text.

Typical bond Calculated bond length No. of classical structures Bone order Interpretation of bond Bond Environment... 

Dannenberg, J. J., Haskamp, J., Masunov, A., 1999, Are Hydrogen Bonds Covalent of Electrostatic A Molecular Orbital Comparison of Molecules in Electric Fields and H-Bonding Environments , J. Chem. Phys. A 103, 7083. 

In summary, NMR techniques based upon chemical shifts and dipolar or scalar couplings of spin-1/2 nuclei can provide structural information about bonding environments in semiconductor alloys, and more specifically the extent to which substitutions are completely random, partially or fully-ordered, or even bimodal. Semiconductor alloys containing magnetic ions, typically transition metal ions, have also been studied by spin-1/2 NMR here the often-large frequency shifts are due to the electron hyperfine interaction, and so examples of such studies will be discussed in Sect. 3.5. For alloys containing only quadrupolar nuclei as NMR probes, such as many of the III-V compounds, the nuclear quadrupole interaction will play an important and often dominant role, and can be used to investigate alloy disorder (Sect. 3.8). 

Vibrational spectroscopy is a very important tool in characterizing the content and local bonding environments of hydrogen in a-Si H (Brodsky et al., 1977a Knights et al., 1978). The infrared absorption... 

The naive concept that a fixed set of valence AOs suffices for all charge states and bonding environments is equivalent to the use of a minimum basis set (e.g., STO-3G), which is known to be quite inadequate for quantitative purposes. Nevertheless, if the AOs are properly allowed to adjust dynamically in the molecular environment, one recovers a minimal-basis description that is surprisingly accurate the natural minimal basis. In the NBO framework the effective natural atomic orbitals are continually optimized in the molecular environment, and the number of important NAOs therefore remains close to minimal, greatly simplifying the description of bonding. 

The following question remains Why are the sigma-type interactions weaker than the pi-type interactions in this case This is apparently a geometrical effect, enforced by the relative sizes of M and X valence and core orbitals in the ionic bonding environment, and illustrated in the NAO diagrams of Fig. 2.18. We may... 

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