Cation Regulation to Investigate the Chalcogenide Borate RE 6 Nb 2 MgSB 8 O 26 (RE = La-Nd) Family.

Chalcogenide borates have been developed and are considered an attractive system due to their favorable physical properties such as magnetism and nonlinear optical effects. Here, isostructural RE 6 Nb 2 MgSB 8 O 26 (RE = La-Nd) compounds in the title family have been obtained through cation regulation in rare-earth and VB group metals. This family crystalizes in the centrosymmetric P 3̅ space group and features 3D frameworks formed by {[Mg(NbB 4 O 13 ) 2 ] 16- } ∞ polyanionic layers and QRE 6 octahedra. The structural chemistry was characterized and theoretical calculations were performed to understand the structural merit of this family. In addition, RE 6 Nb 2 MgSB 8 O 26 possess the largest band gaps among known rare-earth chalcogenide borates, and they all show antiferromagnetic-like behaviors.