High-pressure Synthesis and Characterization of the Rare-earth Fluoride Borate LaB₂O₄F

Abstract

The rare-earth fluoride borate LaB 2 O 4 F was synthesized under high-pressure/high-temperature conditions of 1.1 GPa and 1300 • C in a Walker-type multianvil apparatus from lanthanum oxide, lanthanum fluoride, and boron oxide. The single-crystal structure determination revealed that LaB 2 O 4 F is isotypic to CeB 2 O 4 F. The compound crystallizes in the orthorhombic space group Pbca (no. 61) with eight formula units and the lattice parameters a = 8.2493(9), b = 12.6464(6), c = 7.3301(5)Å, V = 764.7(2)Å 3 , R 1 = 0.0354, and wR 2 = 0.0474 (all data). The structure exhibits a 9+1 coordinated lanthanum cation, one threefold coordinated fluoride ion and a chain of corner-sharing [BO 3 ] 3− groups. In addition to the IR-and Raman-spectroscopic investigations, DFT calculations were performed to support the assignment of the vibrational bands.

Structure, Thermal Behavior, and Vibrational Spectroscopy of the Silver Borate AgB3O5

“…For all other atoms, a triple‐zeta basis set was chosen 37. The PBESOL functional38 was chosen for the calculations of the correlation and exchange energies, as its reliability was proven by previous solid‐state frequency calculations 39. An energy minimization was performed before the theoretical IR and Raman spectra were calculated.…”

The synthesis of novel lanthanum hydroxyborate at extreme conditions

“…The positional disorder of the BO 3 groups is unusual for known RE borates and has never been described before. In terms of a three-fold coordinated boron atom, in RE borates BO 3 group can form either linked chains [for example, in α-Sm(BO 3 ) 2 ( Fuchs et al, 2020a ) or in LaB 2 O 4 F ( Hinteregger et al, 2013b )], or isolated triangles [for instance, in NdBO 3 ( Müller-Bunz et al, 2003 ) or in Dy 5 (BO 3 ) 2 F 9 ( Hinteregger et al, 2013a )]. The arrangement of boron groups in most cases is coplanar (parallel to one plane) or slightly distorted.…”

First ternary tungsten tellurate(iv) WTe2O7 with unique crystal structure type

“…The observed shifts in the calculated vibrational wavenumbers are not uncommon and also occurred in spectral data of previously investigated systems. [58][59][60] Both Te atoms in WTe 2 O 7 are bisphenoidal coordinated with two longer axial (ax = axial) and two shorter equatorial (eq = equatorial) bonded oxygen atoms forming [TeO 4 ] 4− units. A similar situation exists for α-TeO 2 , where the stronger Te-O eq vibrations have been assigned above 600 cm −1 , while the weaker Te-O ax modes appear between 400 and 500 cm −1 .…”