Formation of Edge-Sharing BO4 Tetrahedra in the High-Pressure Borate HP-NiB2O4

摘要

In the course of our structural investigations of borates synthesized under high-pressure, high-temperature conditions, we discovered several new high-pressure modifications with interesting structural features and physical properties, for example, a new non-centrosymmetric modification of bismuth triborate ((5-BiB3O6). Along with the investigation of these phase transitions, we aim to synthesize borates with new compositions, whose existence is presumably based on high-pressure conditions during synthesis. Examples are the borates RE3B5On (RE = Tm-Lu), RE4B6O_(15) (RE = Dy, Ho), alpha-RE2B4O9 (RE = Sm-Ho), beta-RE2B4O9 (RE = Gd, Dy), and Pr4B_(10)O_(21), which have no corresponding ambient-pressure modifications.