Chapter 5 - Volume-based thermodynamics approach in the context of solid-state chemical reactivity analysis

Abstract

Reactivity belongs to the objects of theoretical chemistry in the broadest sense, as it embodies both thermodynamic and kinetic factors. Volume-based thermodynamics (VBT) is a successful tool for the prediction of solid-state chemical reactivity of organic and inorganic chemical systems. The VBT approach (VBTA) introduced by Jenkins and Glasser is widely accepted in calculating important solid-state properties, such as lattice energy, ambient isobaric heat capacities, standard absolute entropy, surface tension, and in the prediction of global phase stability. Without any sophisticated calculations, using mainly the molar volume of the chemical systems, the above thermodynamic properties are easily calculated. In addition to ionic solids, VBT can be applied to ionic liquids and amorphous materials without any knowledge of crystal structure. The reasons why Jenkins, Glasser and other groups prefer the molar volume in such correlations are discussed. This chapter presents important details about the volume-based thermodynamics approach and its applications in chemistry. Methods to additionally include covalent interactions in solids are discussed. We compare the performance of the VBTA with that of conceptual density functional theory (CDFT) and conceptual Ruedenberg theory (CRT). The solids showing systematic positive and negative deviations within the simple VBTA, that is, the alkali metal hydrides and the coinage metal monohalides, respectively, are well assessed by the CRT, which is also successful for the alkali metals. We further test CDFT and CRT by involving electronic structural rules, like the minimum electrophilicity and minimum polarizability rules. The VBTA and the minimum polarizability rule support each other. Kaya's composite descriptor to compute the lattice energies of inorganic ionic crystals combines the chemical hardness of the molecule with VBTA molar volume of the solid. Solid-state double-exchange reactions are best assessed by Kaya's composite descriptor, somewhat less by the CRT valence-state electrophilicity index ω2 but not at all by the CDFT index ω1. Additionally, some equations showing significant relations of chemical hardness and Fukui potential with lattice energy are presented.