Sublimation Born-Haber cycle

In the Born-Haber cycle for the formation of NaCl, S is the sublimation enthalpy of Na,... 

The straightforward extrapolations of KeUer et al. of the physical and chemical properties of elements 113 and 114 are mainly based on the fact of the simple outer electronic structure of 7 i/2 and 7 i/2, with their large energetic and radial separation to the 7s and Qd electrons. As an example of these predictions, which are listed in Table 5, Fig. 16 shows the very suggestive extrapolations of the heat of sublimation of elements 113 and 114, and Fig. 17 the extrapolation of the melting point of element 113. The second important quantity for the derivation of the standard electrode potential through the Born Haber cycle is the ionization... 

Most of the enthalpies associated with steps in the cycle can be estimated, to a greater or less accuracy, by experimental methods. The lattice energy, however, is almost always obtained theoretically rather than from experimental measurement. It might be supposed that the enthalpy of dissociation of a lattice could be measured in the same way as the enthalpy of atomization of the metal and nonmctal, that is, by heating the crystal and determining how much energy is necessary to dissociate it into ions. Unfortunately, this is experimentally very difTicull. When a crystal sublimes (AHj), the result is not isolated gaseous ions but ion pairs and other clusters. For this reason it is necessary to use Eq. 4.13 or some more accurate version of it. We can then use the Born-Haber cycle to check the accuracy of our predictions if we can obtain accurate data on every other step in the cycle. Values computed from the Bom-Haber cycle are compared with those predicted by Eq. 4.13 and its modifications in Table 4.3. 

P20.16 The problem asks for an estimate of Ar// (CaCI). A Born-Haber cycle would envision formation of CaCl(s) from its elements as sublimation of Ca(s), ionization of Ca(g), atomization of Cbfg) electrom gain of Cl(g), and formation of CaCl(s) from gaseous ions. Therefore... 

Fig. 1.4 Schematic Born-Haber cycle for the formation of solid NaCI the energetic data (kJ/mol) are Na sublimation enthalpy AHsubi = 100.5 x CI2 dissociation enthalpy H iss = 121.4 Na ionization energy I = 495.7 Cl electron affinity A = -360.5 experimental reaction enthalpy AHr = -411.1.

Figure 2.39 Born-Haber cycle for calculation of sublimation enthalpies from enthalpies...

Born-Haber cycle. The cycle that relates lattice energies of ionic compounds to ionization energies, electron affinities, heats of sublimation and formation, and bond enthalpies. (9.3)... 

Write a Born-Haber cycle for the formation of CaH2 and use it to calculate a value for the lattice energy of this compound. (The standard heat of formation of CaH2 is 186 kJ/mol the heat of sublimation and the first and second ionization energies of calcium are 178.2,589.8, and 1145 kJ/mol, respectively other thermochemical quantities can be found in Table 10.3.)... 

The values given by Miedema are the formation enthalpies of solid solutions of A in B or vice versa. The solved metal is embedded into the matrix of the solvent. Using a Haber-Born cycle as shown in Figure 2.39 the sublimation enthalpy of the solved metal embedded in the matrix of the solvent can be calculated. Results of sublimation enthalpies of the solved metal embedded in the matrix of the solvent are shown in Table 2.4b. 

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