A very rare area negative thermal expansion phenomenon is observed in a newly discovered alkali beryllium borate LiBeBO3, which is characterized by [BeBO3]∞ double layers intraconnected by edge-sharing BeO4 tetrahedra. This unusual thermal behavior is attributed to the combined vibrational effects of the abnormal Be–O structures and Li+ cations.Chemical Communications, 2014 Structure of LBBO. (a) Schematic diagram view along the b-axis. The green triangles and gold polyhedra represent [BO3] groups and [BeO4] tetrahedra, respectively. (b) The layered [BeBO3]∞ structure in the ab plane. Thermal expansion behavior of the LiBeBO3 (a) variation in a, b and c axes verses temperature. (b) Normalized components of the principal axes verses temperature, where X, Y, and Z are −3.31(13) MK−1, −1.76(08) MK−1, and 7.58(76) MK−1, determined by the PASCAL program. |
