From BaAl2(BO3)2O to SnAl2(BO3)2F2: structure transformation based on ion regulation

Abstract

Using BaAl₂(BO₃)₂O as a structural template to explore the Sn–Al–B–O–F system, a new tin(II)-containing aluminum borate fluoride compound, SnAl₂(BO₃)₂F₂, was synthesized successfully using the high-temperature solution method in a closed system. It possesses AlBO₆F₂ units which are interconnected further to form Al–B–O–F channels, and the Sn atoms reside in the related channels. To the best of our knowledge, SnAl₂(BO₃)₂F₂ is the first case with isolated BO₃ groups in tin(II) borates. The UV-vis-NIR diffuse reflectance spectrum indicates that its ultraviolet (UV) cutoff edge is about 240 nm. Furthermore, the first-principles calculations of SnAl₂(BO₃)₂F₂ were carried out.