High‐pressure/High‐temperature Synthesis of ErCd2B7O13(BO(OH)3): A Non‐centrosymmetric Erbium Cadmium Borate

Abstract Explorative high‐pressure/high‐temperature syntheses (7 GPa, 800 °C) starting from Er 2 O 3 , CdO, and H 3 BO 3 yielded single‐crystals of the hitherto unknown compound ErCd 2 B 7 O 13 (BO(OH) 3 ). This compound crystallizes trigonally in the non‐centrosymmetric space group R 3 c with the unit cell parameters a =8.8418(2) Å, c =22.4972(8) Å, and six formula units per cell. The crystal structure is composed of corner‐sharing trigonal planar [BO 3 ] and tetrahedral [BO 4 ] groups, forming a complex three‐dimensional framework. In this article, the structural data and characteristics of ErCd 2 B 7 O 13 (BO(OH) 3 ) are presented in detail. Furthermore, the compound's infrared spectrum is discussed.