Sr 3 B 14 O 24 : a new borate with a [B 14 O 30 ] fundamental building block and an unwonted 2D double layer.

A new alkaline-earth metal borate, Sr 3 B 14 O 24 , was successfully synthesized by a high-temperature solution method. It crystallizes in the monoclinic space group P 2 1 / c (no. 14) and features a fundamental building block (FBB) [B 14 O 30 ] which is composed of eight [BO 3 ] and six [BO 4 ] units. The FBBs further condense to form an unwonted infinite 2D double layer extended in the bc plane. The UV-Vis-NIR diffuse reflectance spectrum shows that the cutoff edge of Sr 3 B 14 O 24 is less than 200 nm, which indicates its potential use in the deep UV region. In addition, the first principles theoretical study was carried out to better understand the relationship between the structure and performance.