Bond dissociation eneigy

Bodenstein approximation, 101 Boltzmann constant, 202 Boltzmann distribution, 157, 201 Bond dissociation curve, 191, 293 Bond dissociation eneigy, 196 Bond order, 223 Borderline reactions, 429 Bom equation, 408... 

TABLE 2. Total energies (a.u.) of < timized complexes AuL+, charges q on atoms and bond dissociation eneigy BDE (kcalmol ) to Au +L... 

The latter equation contains constants with well-known values and can therefore be used to predict the fracture stress of most polymers. For example, the bond dissociation eneigy Do, is about 80 kcal/mol for a C-C bond. For polystyrene, the modulus E 2 GPa, A.4, p = 1.2 g/cm. Me = 18,000, and we obtain the fracture stress, or 47 MPa, which compares well with reported values. Polycarbonate, with similar modulus but a lower M<, = 2,400 is expected to have a fracture stress of about 100 MPa. In general, letting E 1 GPa, p = 1.0 g/cm, and Do = 335 kJ/mol, the tensile strength is well approximated by... 

Molecule (C— H bond in boldface) Description Bond dissociation eneigy (kJ/mol) StabUity of radical ... 

Grant DJ, Matus MH, Switzer JR, Dixon DA (2008) Bond dissociation eneigies in second-row compounds. J Phys Chem A 112 3145-3156... 

Fig. 2.5 Energy level diagram depicting how REs are calculated using the thermodynamic cycle. R = [M + nH](" EA(A) = proton affinities of A, and D(RA) = bond dissociation eneigies...

Fig. 17.12 Bond dissociation eneigies and bond lengths of the hydrogen halides, methyl halides, and halogen molecules. Note that this figure, which is taken directly from Politzer s work, portrays in a difiTerenl way rdalionships that are closely relaled to Fig. 9.7. [From Folitzer. P. J. Am. Chem. Soc. 1969. 91.6235. Reproduced with pemiission. ...

Table 1 Bond dissociation eneigy values of the main covalent bonds in commercially available organic pol5nners and the corresponding wavelength [2]...

Table 23 The bond dissociation eneigies (M-Ceo) (kcal/mol), metal-carbon, carbon-carbon dis-...

Table 2.5 Bond dissociation eneigies BDE (kcal/mol) rmd dipole moment /r (Debye) ...

A. Bond Dissociation Energies and Divalent State Stabilization Eneigies. 129... 

A bond dissociation energy is the AH° for a specific kind of reaction— the homolysis of a covalent bond to form two radicals. Because bond breaking requires eneigy, bond dissociation energies are always positive numbers, and homolysis is always endothermic. Conversely, bond formation always releases energy, so this reaction is always exothermic. The H-H bond requires +104 kcal/mol to cleave and releases -104 kcal/mol when formed. Table 6.2 contains a representative list of bond dissociation energies for many common bonds. 

Table 5.2 Typical bond lengths and dissociation eneigies for some selected primary bonds...

The most stable chemical form of nitrogen in aerated soil solutions is nitrate (NO ), yet N2 gas is prevalent in the air of soil pores. Oxidation of N2 to nitrate, a thermodynamically favored reaction in aerated soils, is made difficult by the high bond order of N2. The N—N triple bond has a formidably high dissociation eneigy of 225 kcal/mole, and biological organisms have not evolved enzymatic systems to... 

Sanche, L. 2010. Low-eneigy electron interaction with DNA Bond dissociation and formation of transient anions, radicals, and radical anions. In Radical and Radical Ion Reactivity in Nucleic Acid Chemistry, ed. M.M. Greenberg, pp. 239-93. Hoboken, NJ John Wiley Sons. 

Harrison WA (1980) Electronic structure the properties of solids. Freemtm, San Fiancisco Zavitsas AA (2003) The relation between bond lengths and dissociation eneigies of carbon-carbon bonds. J Phys Chem A 107 897-898... 

The application of methods of valent bond and molecular orbitals to complex structures faces significant obstacles for prognosticating energy characteristics of the bonds formed. Based on the Eq. (4.6), the application of the formula for calculating the dissociation eneigy has turned out to be practically suitable [12] ... 

Resonances with pure excitation of the CO stretching mode (0, U2, 0) (an example with Vi - 8 is shown in Fig. 5) have the smallest rate and therefore the longest lifetime energy transfer from r to R is rather inefficient, and therefore the system needs a long time before enough eneigy is accumulated in the dissociation coordinate to permit dissociation. On the other extreme, direct excitation in R allows a rather rapid bond rupture, and therefore the resonances (t>i, 0, 0) have the shortest lifetimes. Excitation of the bending mode (0,0, U3) leads to lifetimes that are between C-O excitation as the lower limit and H-C excitation as the upper extreme. This mode specificity is further elucidated in Fig. 8, where we show the widths for several... 

Fig. 5.15. The CASSCF dissociation of the C2t, water molecule in the cc-pVDZ basis (atomic units) for a fixed HOH bond angle of 110.565° On the left, we have plotted the potential-eneigy curves of the valence CASSCF wave function (black line) and the FCI wave function (grey line) on the right, we have plotted the difference between the energies of the valence CAS wave function and the FCI wave function.

---