The Rubidium Barium Borate Resulting from BO Fundamental Building Block Exhibits DUV Cutoff Edge.

The first rubidium barium borate, RbBaBO, has been prepared. Through analysis of single crystal structures, RbBaBO is built from a three-dimensional [BO] framework with two types of channels which are occupied by Rb and Ba ions. The connection style of the fundamental building block (FBB) BO is different from that of B-O FBBs existing in the other borates, which can be determined as the unprecedented unit. The structural performance relationship can be better understood by combining first-principles calculations and experimental results. For the RbBaBO, the indirect energy gap is 5.96 eV, which matches the experimental data (wavelength absorption < 190 nm). IR spectroscopy and thermal analysis have also been characterized. What's more, for all the available anhydrous hepta-borates, the structure comparisons about FBBs were carried out.