Mean bond dissociation energies

Table II. Mean Bond Dissociation Energy Data for Some Early Transition Metal Complexesa and Estimated 5 Values for Thorium and Uranium.

Fig. 4. Variation of the mean bond dissociation energy D (M-Cp) kJ mol-1 in MCp2 (M = Ti,...

Fig. 6. Variation of the mean bond dissociation energy, D (MH-Cp) kJ mol-1, in MCp2 (M = Ti, V, Cr, Mn, Fe, Co, Ni) with average metal-cyclopentadienyl ring plane distance in well determined structrues (Ref.73)) r(M-Cp) pm. See Table 9...

The mean bond dissociation energies (E ) given in Table 12 are based on thermochemical data at 25 C19. Unless previously discussed, the heat of formation of the metal alkyl used is that given by Long60. The higher values of E and D2 for dimethyl mercury are obtained when Long s recommended value for the heat... 

Much of the enthalpy of formation data for the dialkylzincs was reported from two separate sources in 1949 . From these measurements each group derived the mean bond dissociation energies of the diaUcylzinc compounds. From Reference 12, the mean C—Zn bond energies were 172 kJmor for MeaZn and 150 kJmoU for EtaZn (and by assumption for the n-Pr2Zn and n-Bu2Zn species also). From Reference 18, the mean bond energies for the MeiZn and Et2Zn compounds were reported as 171 and 144 kJmoU, respectively. 

MEAN BOND DISSOCIATION ENERGIES, D, AND BOND DISSOCIATION ENERGIES, D, IN... 

Table 20. Mean bond dissociation energy (BDE) of various classic deavable bonds of telogens [21,322,323] ...

Table 1 Mean bond dissociation energies for some R2M (M = Zn, Cd, Hg) compounds...

Table 1 Physical properties and mean bond dissociation energies of some diorganozinc compounds...

The occurrence of stable neutral. binary carbonyls is restricted to the central area of the d block (Table 19.3), where there are low-lying vacant metal orbitals to accept o-donated lone-pairs and also filled d orbitals for jr back donation. Outside this area carbonyls are either very unstable (e.g, Cu, Ag, p. 1199), or anionic, or require additional ligands besides CO for stabilization. As with boranes and carboranes (p, 181), CO can be replaced by isoelectronic equivalents such as 2e , H , 2H or L. Mean bond dissociation energies Z>(M-CO)/kJ mol increase in the sequence Cr(CO)fi 109, MoCCO>6 151. W(CO)6 176, and in the sequence Mn2(CO)so lOO, Fe(CO)s 121, Co2(CO)g 138. NiCCO)4 147. 

To illustrate the picture as given above, selected mean bond dissociations energies (BDE) for various TMHs are sketched in Figure 1 [9]. 

F ure 1. Mean bond dissociation energies for selected TMHs (in kJ/mol Cp = CjMe ). Data taken from ref. 9. 

Ref. 15a. Experimental intrinsic mean dissociation energy D(M-CO), Ref. 15a. Mean bond dissociation energy. 

This leads to the idea of a mean bond dissociation energy 2>(C—H), which in this particular case is identical with the bond energy. In a molecule containing more than two different atoms, the two terms would not be synonymous. 

Mean Bond Dissociation Energies 1, Representative and h-Group Elements... 

Steele, W. V., The Standard Enthalpy of Formation of Tetraphenylsilane and the Ph-M Mean Bond-Dissociation Energies of the Group IV Elements, J. Chem. Thermodyn. 10 [1978] 445/52. 

---