Standard molar enthalpies of formation of lithium alkoxides

Abstract

The standard ( p 0 = 0.1 MPa) molar enthalpies of formation of several crystalline lithium alkoxides, Δ H f 0(LiOR, cr), have been determined by reaction-solution calorimetry at 298.15 K. A linear correlation has been found between Δ H f 0(LiOR, cr) and Δ H f 0(ROH, 1) for R = n-alkyl, enabling the prediction of data for other lithium alkoxides. The deviations from the linear correlation observed for R  iPr and tBu were tentatively explained in terms of the electronegativities of the OR groups. The experimental data were also used to derive the lattice energies and the thermochemical radii of the anions OR −. The results were compared with those derived from the enthalpies of formation of the analogous sodium alkoxides, reported in a previous publication.