High-pressure/high-temperature synthesis of the new borate Cr ₅₁ Ni ₂₃ B ₁₆₈ O ₃₃₇ (OH) ₂₉

Abstract The compound Cr 51 Ni 23 B 168 O 337 (OH) 29 has been obtained through an explorative high-pressure/high-temperature experiment at 9 GPa and 1,200 °C. This borate crystallizes in the trigonal space group <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <m:mrow> <m:mi>R</m:mi> <m:mover> <m:mn>3</m:mn> <m:mo>‾</m:mo> </m:mover> <m:mi>m</m:mi> </m:mrow> </m:math> $R\overline{3}m$ with the unit cell parameters a = 10.4387(1), c = 51.5121(1) Å, V = 4,861.1(2) Å 3 , and one formula unit per cell. The crystal structure is a complex framework, composed of corner-sharing tetrahedral [BO 4 ] groups and edge-sharing [(Cr,Ni)O 6 ] octahedra. In this contribution, the structural data and the infrared spectrum of Cr 51 Ni 23 B 168 O 337 (OH) 29 are presented.