Area negative thermal expansion in a beryllium borate LiBeBO₃with edge sharing tetrahedra

Abstract

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.