Physical measurements on (I) some boron-containing compounds and (II) some aqueous inorganic ions

Abstract

The synthesis and stability of dioxaborepan systems have been investigated. These heterocycles are considerably less stable than the dioxaborinan and dioxaborolan analogues. The thermal stability of some bisdichloroborinates and derived esters has been studied and a mechanism for the disproportionation is discussed. The association in the solution phase of some inan and olan heterocycles was investigated cryoscopically. Associative models are proposed and discussed. B-chloro derivatives of the above systems have been studied thermo-chemically in solution and relevant enthalpies of formation and hydrolysis derived. Data on the heat of solution of some diols is also reported. The accuracy of the calorimetric procedure was checked by the measurement of the heat of solution of anionic thermochemical standard. This type of measurement was extended to other ionic systems and other thermodynamic functions derived. This investigation comprises Part II of this thesis. This section is concerned with the determination of lattice energies and related thermodynamic functions of some simple ionic salts of the main groups I and II. Lattice energies are derived principally via the use of empirical correlations between (i) lyotropic number and hydration enthalpy and (ii) anion radius and hydration enthalpy. Interpolated hydration enthalpies are introduced into a simple Born-Haber cycle involving the heat of solution of the salts. The accepted data of Latimer et al. is used for Group I salts and the recent data of Noyes extended to include Group II salts. When sufficient data is available determinations are checked by simple calculation of lattice energy by the method of Kapustinkii. Integral heats of solution for the Group II chlorates have been determined to complete the series of soluble salts of the type [equation] where X = halogen. An attempt was made to correlate the "effective crystal radius" of non-spherically symmetrical ions with an easily accessible property of the ion (e.g. Pauling radius, partial molal volume).