Structure of Aqueous Lithium Tetraborate Solution

Abstract

The structure of aqueous lithium tetraborate solutions was investigated by species distribution calculation and synchrotron X-ray scattering. It shows that the dominant species in supersaturated solution at 298.15 K is B4O5(OH) 4 2− and the minor species are B3O3(OH) 5 2− , B3O3(OH) 4 − and B(OH)3. The ‘intramolecular’ structural parameters of B4O5(OH) 4 2− , such as bond length and coordination number, were gives out using density function theory calculation. X-ray scattering study shows that the distance Li–O(H2O)I of [Li(H2O)4]+ is about 0.1983 nm with the coordination number(CN) 4 in tetrahedral configuration. The B–O(H2O) distance in hydrated anion B4O5(OH)4(OH2) 8 2− is 0.3662 nm with the CN 12. The Li+–B distance is about 0.3364 nm with a coordination number ~1.0. The temperature effect on solution structure was also discussed.