Bond energies of metals

The bond energy of main group and transition metals of an atom in an ideal kink site 

In the process of sublimation the atom is separated from a special position on the surface, the kink site position (half crystal position). In the ideal kink site position the 

Sublimation enthalpies, energies of atoms in ideal kink positions and bond energies between the two nearest atoms, main group and transition metals  

The Gibbs energy of an atom in the ideal kink site position is the characteristic value for the molecular interaction of the atom with the bulk matrix. It takes into account bond strengths among first, second, and further neighbors. It is exactly one half of the lattice energy. 

The Gibbs energy of an atom in the kink position (chemical potential) can be derived from the sublimation enthalpy (Vohner ) a discussion is also found in the book of Budevski, Staikov and Lorenz.  

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Table 13. Bond energies (/>) of metal-carbon or metal-hydrogen bonds and activation energies ( ) of the insertion of ethylene into these t>onds...

Aristov and Armentrout (25) and Freiser ct al. (26.27) derived the bond energies of metal-carbon triple bonds from gas-phase experiments. The values are listed in Table III. Table 111 also lists bond energies for metal-carbon double and single bonds. 

Empirical models have been developed to predict the bond energies of metallic and intermetallic molecules, such as the following the Pauling model of a polar single bond [174], the valence bond model for certain multiply bonded metallic molecules by Brewer [175] and Gingerich [176], and the macroscopic atom or atomic cell model by Miedema and Gingerich [177]. 

Bond energies of gaseous polyvalent metal halides... 

The resulting data for liquid metals indicate a systematic relationship witlr the bonding energy of the element, which is reflected in the heat of vaporization... 

This qualitative description of the interactions in the metal is compatible with quantum mechanical treatments which have been given the problem,6 and it leads to an understanding of such properties as the ratio of about 1.5 of crystal energy of alkali metals to bond energy of their diatomic molecules (the increase being the contribution of the resonance energy), and the increase in interatomic distance by about 15 percent from the diatomic molecule to the crystal. 

C08-0076. Calculate the overall energy change for the formation of lithium fluoride from lithium metal and fluorine gas. hi addition to data found in Appendix C and Table 8-4. the following information is needed The bond energy of F2 is 155 kJ/mol, and lithium s enthalpy of vaporization is 159.3 kJ/mol. 

Carbon in the form of diamond is an electrical insulator because of its huge band gap. hi fact, its band gap of 580 kJ/mol substantially exceeds the C—C bond energy of 345 kJ/mol. In other words, it requires more energy to promote an electron from band to band in diamond than to break a covalent bond. Lead, in contrast, is a metallic conductor because it has... 

A free-electron metal only possesses a broad sp band. Upon approach, the electron levels of the adsorbate broaden and shift down in energy, implying that the adsorbate becomes more stable when adsorbed on the metal. The interaction results in a bonding energy of typically 5 eV for atomic adsorbates on metals. The situation is illustrated in Fig. 6.23. 

This type of side-on bending, which has been established by X-ray crystallographic methods for the related acyl complexes (r 5-C5H5)2Zr(COMe)Me (38) and (T>5-C5H5)2Ti(COMe)Cl (39), could overcome the thermodynamic objection, previously discussed, against the formation of a normal, linearly bonded formyl by CO insertion into a metal-hydride bond. Thermochemical data obtained from alcoholysis of zirconium tetralkyl species show that the mean bond energy of Zr—O is 50 kcal/mole greater than that of Zr—C (40). 

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