High-pressure synthesis and crystal structure of the lithium borate HP-LiB3O5

The new lithium borate HP-LiB3O5 was synthesized under high-pressure/high-temperature conditions of 6 GPa and 1050 °C in a multianvil press with a Walker-type module. The compound crystallizes in the space group Pnma (no. 62) with the lattice parameters a=829.7(2), b=759.6(2), and c=1726.8(4) pm (Z=16). The high-pressure compound HP-LiB3O5 is built up from a three-dimensional network of BO4 tetrahedra and BO3 groups, which incorporates Li+ ions in channels along the b-axis. Band assignments of measured IR- and Raman spectra were done via quantum-mechanical calculations. Additionally, the thermal behavior of HP-LiB3O5 was investigated.

Graphical abstractThe new high-pressure compound HP-LiB3O5 is built up from a three-dimensional network of BO4 tetrahedra and BO3 groups, which incorporates Li+ ions in channels along the b-axis. In this paper, the synthesis, the crystal structure, and the properties of HP-LiB3O5 are described.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Synthesis of a new lithium borate with the composition HP-LiB3O5 at high pressure. ► In contrast to the non-centrosymmetric phase LiB3O5, this high-pressure phase is centrosymmetric. ► First example of ternary alkali borates exhibiting threefold bridging oxygen atoms.