Microstructure for aqueous cesium tetraborate and rubidium tetraborate with X-ray scattering

摘要

In this study, microstructure such as intra-molecule interaction B-O,O-O in polyborate anions (B3O3(OH)(4)(-), B4O5(OH)(4)(-)) and inter-molecule (B-O(W),M(Rb/Cs)-O, M(Rb/Cs)-B and O-O, M-M i.e.) interaction have been taken into consideration by model calculation with the method of X-ray scattering. The models of B3O3(OH)(4)(-), B3O3(OH)(5)(2-) and B4O5(OH)(4)(2-) were optimized by DFT (density functional theory) calculation which have a good agreement with the model calculation. During the process of data analyzing, Raman spectrum, pH, density, stoichiometric volume, atomic mass absorption coefficient have also been carried out. The coordination distance and number of Cs-O(wI)(similar to 0.336 nm, similar to 7.8), Cs-O(wII)(similar to 0.526 nm, similar to 8.4), O-O(W)(similar to 0.278 nm, similar to 2.15) and Cs-B(similar to 0.458 nm, similar to 0.9) are concerned to Cs2B4O7 solution. For aqueous Rb2B4O7 samples, the structure parameters of Rb-O(wI)(similar to 0.292 nm, similar to 7.0), Rb-O(wII)(similar to 0.467 nm, similar to 8.0), O-O(W)(similar to 0.278 nm, similar to 2.22), Rb-B(similar to 0.377 nm, similar to 0.9) are also listed in the discussion part. And also concluded that cesium ion forms bidentate chelate complexes with tetraborate ion in the solution. Moreover, the influence of the samples' concentration on RDFs (radial distribution function curves) and the difference between cesium tetraborate and rubidium tetraborate also illustrated in paper. (C) 2019 Published by Elsevier B.V.