Ionic bonds energy involved

T jr provides an estimate of an ion s propensity to form ionic bonds. For elements that are susceptible to covalent interactions, reactivity is best predicted by also considering their electronegativity, which is defined as the power of an atom in a molecule to attract electrons to itself. (Strictly considered, the electronegativity of an atom depends on its oxidation state and the energy levels of the valence electron(s) involved in the covalent interaction.)... 

Thermochemical data for the solvation of ions as used in the preceding calculations are difficult to measure and even to estimate. Therefore this kind of calculation of AH° for ionic reactions involving organic molecules in solution usually cannot be made. As a result, we have considerably fewer possibilities to assess the thermodynamic feasibility of the individual steps of polar reactions in solution than we do of vapor-phase radical processes. Bond energies are not of much use in predicting or explaining reactivity in ionic reactions unless we have information that can be used to translate gas-phase AH°. values to solution AH° values. Exercise 8-3 will give you a chance to see how this is done. 

The sum of (1) + (2) + (4) is very like the attractive energy of an ionic bond formed from atoms A and B and involving a partial charge, x, while (3) is a covalence energy for a bond of fractional order (1 — x). The... 

In the actinide series, therefore, the energies of the 5f 6d, Is, and Ip orbitals are about comparable over a range of atomic numbers (especially U to Am), and since the orbitals also overlap spatially, bonding can involve any or all of them. In the chemistries this situation is indicated by the fact that the actinides are much more prone to complex formation than are the lanthanides, where the bonding is more ionic. The difference from lanthanide chemistry is usually attributed to the contribution of covalent hybrid bonding involving 5/ electrons. 

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