A Crystallographic Review of Alkali Borate Salts and Ab Initio Study of Borate Ions/Molecules

A Raman spectroscopic and ab initio investigation of aqueous boron speciation under alkaline hydrothermal conditions: evidence for the structure and thermodynamic stability of the diborate ion

“…Ab initio computational studies on these species were carried out at several levels of theory, with and without solvation, as discussed in the following section. Selected gas-phase structures were taken from previous studies of Pye et al 21,25 The structures of the diborate species derived from these calculations in this study are shown in Fig. 5.…”

“…Based on the known spectra of the boric acid/borate solutions at 25 °C, 9 Ab initio computational studies on these species were carried out at several levels of theory, with and without solvation, as discussed in the following section. Selected gasphase structures were taken from previous studies of Pye et al 21,25 The structures of the diborate species derived from ] 0 , was explored computationally. Initial attempts to locate a C s -symmetric dimer with a single bridging hydroxyl group resulted in dissociation to a hydrogen-bonded boric acid dimer [B(OH) 3 ] 2 , thus systematic desymmetrization from a high symmetry structure was attempted.…”

“…Based on the known spectra of the boric acid/borate solutions at 25 °C, 9 Ab initio computational studies on these species were carried out at several levels of theory, with and without solvation, as discussed in the following section. Selected gasphase structures were taken from previous studies of Pye et al 21,25 The structures of the diborate species derived from S1 †). The Raman frequencies and the corresponding isotropic Raman activities for the ionic di/triborate species in solution phase are tabulated in Table 2. ]…”

“…Models 2 and 3 were based on the MP2/ 6-311+G* computational values of S B 2 ,745 /S B 2 , 865 for [B 2 (OH) 7 ] − and [B 2 O(OH) 5 ] − , respectively, in Table 2. Although computational Raman scattering intensities are known to be quite unreliable, 21,25 the calculated relative Raman intensities of two bands within the same molecule are expected to be more accurate.…”

“…Full details of the computational methods are reported elsewhere. 21 The Raman intensities and depolarization ratios were calculated by default for Hartree-Fock calculations; for B3LYP and MP2 calculations, these were done by specifying Freq = Raman. For selected structures, the process was repeated with the conductor-like polarizable-continuum solvation model (SCRF = CPCM).…”