Solid State Energetics

We start this second and last chapter on the solid state with a description of the theoretical determination of lattice energy. Next, we consider how the lattice energy can be determined experimentally using the principles of thermochemistry that you learned in previous chemistry courses. A discussion of such topics as the degree of covalent character in ionic crystals, the source of values for electron affinities, the estimation of heats of formation of unknown compounds, and the establishment of thermochemical radii of polyatomic ions follows. We conclude with a special section on the effects of crystal fields on transition metal radii and lattice energies. 

In Chapter 1 the differences between ionic and covalent bonding were briefly discussed. This chapter looks more closely at the principles and energetics of the ionic model, in particular how ions are assembled to form structures and what factors can be used to predict the stability of theoretical structures. 

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Glasser, L., Solid-state energetics and electrostatics Madelung constants and Madelung energies, Inorg. Chem. 51 (4), 2420-2424 (2012). 

LATTICE ENERGIES AND IONIC RADII CONNECTING CRYSTAL FIELD EFFECTS WITH SOLID-STATE ENERGETICS ... 

We have seen that Max Born was a prominent contributor to the early days in solid-state energetics. He and Fritz Haber formulated the Born-Haber cycle in 1917, and Born and Alfred Lande formulated the Born-Lande equation in 1918. Many years later, in 1954, Born received the Noble Prize in Physics. For what discovery did he receive this prize Cite a source for your answer. 

What is the reason for these similarities Primarily it is a size effect. The Hthium and magnesium ions (ionic radii = 0.73 A and 0.86 A, respectively) are of appropriate size to fit into a lattice formed by oxide ions (ionic radius = 1.26 A) such that the attraction of cations and anions is maximized and the repulsions between the larger anions is minimized. (See Chapter 8 for more details on solid-state energetics.) The carbonate and nitrate anions (radii = 1.78 A and 1.79 A, respectively) are just large enough that they get in one another s way, and their mutual repulsions become more of a dominant factor. Accordingly, the carbonates and nitrates decompose to the more energeticaUy favorable oxides. 

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