Lattice energies and

In this discussion, entropy factors have been ignored and in certain cases where the difference between lattice energy and hydration energy is small it is the entropy changes which determine whether a substance will or will not dissolve. Each case must be considered individually and the relevant data obtained (see Chapter 3), when irregular behaviour will often be found to have a logical explanation. 

Watson G W, P Tschaufeser, A Wall, R A Jackson and S C Parker 1997. Lattice Energy and Free Energy Minimisation Techniques. Computer Modelling in Inorganic Crystallography. San Diego, Academic Press, pp. 55-81. 

Similar observations hold for solubility. Predominandy ionic halides tend to dissolve in polar, coordinating solvents of high dielectric constant, the precise solubility being dictated by the balance between lattice energies and solvation energies of the ions, on the one hand, and on entropy changes involved in dissolution of the crystal lattice, solvation of the ions and modification of the solvent structure, on the other [AG(cryst->-saturated soln) = 0 = A/7 -TA5]. For a given cation (e.g. K, Ca +) solubility in water typically follows the sequence... 

Lattice energies and thermochemistry of hexahalometallate(IV) complexes, A2MX6, which possess the antifluorite structure. H. D. B. Jenkins and K. F. Pratt, Adv. Inorg. Chem. Radiochem., 1979, 22, 1-111 (81). 

The lattice enthalpy can be identified with the heat required to vaporize the solid at constant pressure. The greater the lattice enthalpy, the greater is the heat required. Heat equal to the lattice enthalpy is released when the solid forms from gaseous ions. In Section 2.4 we calculated the lattice energy and discussed how it depended on the attractions between the ions. The lattice enthalpy differs from the lattice energy by only a few kilojoules per mole and can be interpreted in a similar way. 

Madelung constant (A) A number that appears in the expression for the lattice energy and depends on the type of crystal lattice. Example A = 1.748 for the rock-salt structure. 

E O Fischer and H. P. Fritz Recent Studies of the Boron Hydrides William A, Lipscomb Lattice Energies and Their Significance in Inorganic Chemistry T C. Waddington... 

Lattice Energies and Thermochemistry of HexahalometallatedV) Complexes, AjMXg, which Possess the Antifluorite Structure... 

Grant and coworkers [8] studied the dehydration kinetics of piroxicam monohydrate using both model-free and model-fitting approaches in an effort to understand the effects of lattice energy and crystal structure. The dehydration kinetics was found to differ when determined under isothermal and nonisothermal conditions. Ultimately, the dehydration behavior of piroxicam monohydrate was determined by details of the crystal structure, which was characterized by an absence of channels and a complicated hydrogen-bonding network, and ab initio calculations proved useful in understanding the structural ramifications of the dehydration process. 

The energy required to overcome lattice energies and intermolecular or interionic attractions for the dissolution of a solid in a liquid comes from the formation of new attractions between solute and solvent. 

With air in contact with the earth s surface, it is not surprising that several metals are found in ores that contain the metal oxide. Metal replacement reactions are possible because of differences in lattice energies and reduction potentials. One interesting reaction of this type is... 

The hydrated cation Ca2+aq is of prime importance to the aqueous solution chemistry of calcium, and to most of its various roles in biological systems. The relation between lattice energy and hydration energies of the constituent ions determine solubilities, the size of the hydrated cation controls selectivity and the passage of ions through channels, and the work required to remove some or all of the water of hydration is relevant both to... 

Table 1.19 Lattice energy and CFSE for selected spinel compounds. Values of U, E, and from Ottonello (1986). CFSE values calculated with values proposed by McClure (1957). Data in kJ/mole x = degree of inversion.

The MEG model has been extensively used to determine lattice energies and interionic equilibrium distances in ionic solids (oxides, hydroxides, and fluorides Mackrodt and Stewart, 1979 Tossell, 1981) and defect formation energies (Mack-rodt and Stewart, 1979). Table 1.21 compares the lattice energies and cell edges of various oxides obtained by MEG treatment with experimental values. 

Table 1.21 MEG values of lattice energy and lattice parameter for varions oxides, compared with experimental values. Source of data Mackrod and Stewart (1979). C/ is expressed in kJ/mole (in A) corresponds to the cell edge for cnbic snbstances, whereas it is the lattice parameter in the a plane for AI2O3, Fe203, and Ga203 and it is the lattice parameter parallel to the sixfold axis of the hexagonal unit cell in mtiles CaTi03 and BaTi03.

Table 5.12 reports a compilation of thermochemical data for the various olivine components (compound Zn2Si04 is fictitious, because it is never observed in nature in the condition of pure component in the olivine form). Besides standard state enthalpy of formation from the elements (2) = 298.15 K = 1 bar pure component), the table also lists the values of bulk lattice energy and its constituents (coulombic, repulsive, dispersive). Note that enthalpy of formation from elements at standard state may be derived directly from bulk lattice energy, through the Bom-Haber-Fayans thermochemical cycle (see section 1.13). 

Lattice Energies and Their Significance in Inorganic Chemistry T. C. Waddington... 

Waddington, T. C. Lattice energies and their significance in inorganic chemistry. Advan. Inorg. Chem. Radiochem. 1, 158 (1959). 

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