High‐Pressure Synthesis and Crystal Structure of the Highly Condensed Yttrium Borate YB₇O₁₂

Abstract

The yttrium borate YB7O12 was obtained in a high‐pressure/high‐temperature experiment at 10 GPa and 1573 K. The crystal structure was clarified by X‐ray single‐crystal diffraction, where the compound was found to crystallize in the orthorhombic space group Pccn (no. 56) with the lattice parameters a = 11.985(2), b = 6.717(6), c = 7.867(7) Å, and a volume of V = 633.0(1) Å3. Built up exclusively from BO4 tetrahedra, YB7O12 features an exceptionally high degree of condensation, which originates from the finding that every tetrahedron contains two threefold‐coordinated oxygen atoms. The compound was further characterized by X‐ray powder diffraction.

High‐Pressure Synthesis of the Acentric Borate DyB5O8(OH)2

“…This concept is derived from the general concept of condensation found in silicates The dominant structural motive found in high‐pressure borates are [BO 4 ] 5– tetrahedra, which is in contrast to borates synthesized under ambient pressure conditions, where the [BO 3 ] 3– group dominates. Our research has already yielded several examples of highly condensed borates like YB 7 O 12 , β‐Eu(BO 2 ) 3 , or Dy 4 B 6 O 15 …”

High-Pressure Synthesis, Crystal Structure, and Photoluminescence Properties of β-Y2B4O9:Eu3+

“…In the system Y-B-O, only two modifications of YBO 3 [1] (the low-temperature form π-YBO 3 and the high-temperature form µ-YBO 3 ) and the compound Y 17.33 (BO 3 ) 4 (B 2 O 5 ) 2 O 16 [2] (revised formula of Y 3 BO 6 ) were known until 2016. Through the implementation of high-pressure conditions as an additional reaction parameter, three new compositions β-Y(BO 2 ) 3 [3], α-Y 2 B 4 O 9 [4], and YB 7 O 12 [5] could be obtained by our group. As expected, all of the three latter compounds feature boron exclusively in a fourfold coordination by oxygen anions due to the applied high-pressure conditions.…”

“…(2.263-2.652 Å ) and also to other high-pressure yttrium borates like β-Y(BO2)3 (2.383-2.419 Å) [3], α-Y2B4O9 (2.401-2.602 Å)[4], and YB7O12 (2.308-2.659 Å)[5].…”