NH4B11O16(OH)2: a new ammonium borate with wavy-shaped polycyclic 2∞[B11O16(OH)2] layers†
Abstract
The ammonium borate NH4B11O16(OH)2 has been successfully synthesized by a mild hydrothermal method. Its structure features a new fundamental building block (FBB) [B11O18(OH)2], which is composed of a [B5O10] double-ring and two [B3O5(OH)] single-rings via sharing corner oxygen atoms. The FBB further condenses into 2D wavy-shaped polycyclic layers 2∞[B11O16(OH)2] and forms the final framework through hydrogen bonding. Specifically, the effect of the hydroxyl to boron ratio (NOH/NB) on the FBB assembly has been investigated in the ammonium borate system. In addition, the optical and thermal properties of this compound have been studied experimentally. First-principles calculations have also been carried out in order to understand the electronic structure.