Characterization of Barium Borate Frameworks Using Raman Spectroscopy

Abstract

Systematic micro-Raman scattering investigations have been carried out on Sm doped 2(BaO)-n(BO) matrices for n = 4, 5, 8, and 2(BaO)-(NaO)-9(BO) using the 364 nm excitation of an Ar laser. The Raman results have been compared with the known structures of barium tetraborate, barium pentaborate, barium octaborate, and barium sodium nonaborate. An excellent correlation has been found between the BO/BO composition ratios for each product and intensity ratios of the designated BO and BO Raman peaks. Furthermore, the Raman frequencies of both BO and BO groups undergo a systematic blueshift as n increases from four to nine. The shift results from a decrease of the B-O bond lengths for both BO and BO groups as the samples transition from the tetraborate to nonaborate structures. Linear relations (with negative slopes) have been determined between the measured Raman frequencies and B-O bond lengths in the frameworks.

High-Pressure Synthesis, Electronic Properties, and Raman Spectroscopy of Barium Tetraborate BaB4O7 Polymorphs

“…Experimental and calculated Raman-active modes of α-BaB 4 O 7 are shown in Table S1. We managed to find two works dedicated to Raman scattering of the α-BaB 4 O 7 phases. , The spectrum registered in this work is in good agreement with the data of ref (Figure S4) and does not agree with the data for α-BaB 4 O 7 doped with samarium . We believe that the Raman spectra given in the latter work contain bands typical of β-BaB 2 O 4 , namely, the strongest band at about 637 cm –1 , the bands at about 788, 1524, and 1540 cm –1 .…”

The geochemical role of B-10 enriched boric acid in cemented liquid radioactive wastes

“…The other detected bands are at 1646 cm −1 which relates to water [71][72][73]. Bands at 930 cm −1 (NBA solutions) or 960 cm −1 (EBA solutions) also show up, possibly related to B-O bands in complicated heavy molecules containing boron and sodium atoms [74,75]. However, their identification is not established yet.…”