Coulomb attraction and repulsion

Madeluag constant For an ionic crystal composed of cations and anions of respective change z + and z, the la ttice energy Vq may be derived as the balance between the coulombic attractive and repulsive forces. This approach yields the Born-Lande equation,... 

The Orientation of Water Molecules Adjacent to an Ion. Order and Disorder in the Vicinity of Solute Particles. Coulomb Attraction and Repulsion between Ions. Activity Coefficients. The Distance of Closest Approach. Activity Coefficients of Various Solutes. Forces Superimposed on the Coulomb Forces. 

The special properties of electrolyte solutions present both advantages and disadvantages as we attempt to describe these mixtures. A disadvantage is that significant deviations from limiting law solution behavior occur at much lower concentrations for electrolyte solutes than for nonelectrolyte solutes. An advantage is that the coulombic attractions and repulsions in the electrolyte solution dominate other types of interactions. The result is that theoretical descriptions of electrolyte solutions can concentrate on the coulombic interactions. 

Structurally, HMX exhibits conformational polymorphism, as demonstrated in Fig. 9.1. Brill and Reese (1980) analysed the relative stabilities of the a, p and 8 forms in terms of coulombic forces to interpret the thermophysical behaviour of the three forms. They concluded that the chair conformation found in the p modification is more stable than the chair-chair conformation in the other two forms. The relative stability to pyrolysis could also be accounted for by the analysis of the coulombic attractions and repulsions around the molecule in each of the modifications. More recently, Henson et al. (1999) have followed the change in second harmonic generation response during the jS -> 5 phase change, which has long been implicated in the thermal decomposition of HMX (Karpowicz and Brill 1982). 

Equation [23d] has a nice interpretation. The energy of an electron in atomic orbital x is equal to the negative of its Mulliken electronegativity, (/ + A)/2, corrected for charge build-up on atom A, Q. Yaai to which it belongs, corrected in turn for the number of electrons in the x orbital itself (1 - P ), and then corrected by the Madelung terms (Coulomb attractions and repulsions) located throughout the molecule, Q/jY,uj-... 

Intra-atomic forces prove to be simply the Coulomb attractions and repulsions of the positive nuclei and negative electrons for one another. But it is the quantum theory and the Pauli principle which impose a structure on the atom and dictate the rules for the building up of the periodic system of the elements. 

Adsorption of various ions and molecules on electrodes is favored by their interaction with the electrode surface, and also by the squeezing of adsorbate species out of the solution bulk. The latter phenomenon is induced by the difference in free solvation energies AG between the surface layer and in the bulk of the solution. For positive adsorption, AG < 0, which, in its turn, can be caused by a decrease in enthalpy AH < 0) and by an increase of entropy (A5 > 0) as the adsorbate species pass from the solution bulk to the surface. In principle, electrostatic forces can solely induce the interaction of ions with the electrode surface the coulombic attraction and repulsion should result in positive and negative adsorption, respectively. In addition, at a direct contact... 

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