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Zeitschrift für Naturforschung B Contents Vol. 68b (2013)

Z. Naturforsch. 2013, 68b, 1198 – 1206

doi:10.5560/ZNB.2013-3258

High-pressure Syntheses and Characterization of the Rare-earth Fluoride Borates RE₂(BO₃)F₃ (RE = Tb, Dy, Ho)

Ernst Hinteregger¹, Michael Enders², Almut Pitscheider¹, Klaus Wurst¹, Gunter Heymann¹, and Hubert Huppertz¹

¹Institut für Allgemeine, Anorganische und Theoretische Chemie, Leopold-Franzens-Universität Innsbruck, Innrain 80–82, A-6020 Innsbruck, Austria

²Institut für Pharmazie, Leopold-Franzens-Universität Innsbruck, Innrain 52c, A-6020 Innsbruck, Austria

Reprint requests to H. Huppertz. E-mail: Hubert.Huppertz@uibk.ac.at

Received August 10, 2013 / published online November 4, 2013

The new rare-earth fluoride borates RE₂(BO₃)F₃ (RE = Tb, Dy, Ho) were synthesized under high-pressure/high-temperature conditions of 1.5 GPa/1200 °C for Tb₂(BO₃)F₃ and 3.0 GPa/900 °C for Dy₂(BO₃)F₃ and Ho₂(BO₃)F₃ in a Walker-type multianvil apparatus from the corresponding rare-earth sesquioxides, rare-earth fluorides, and boron oxide. The single-crystal structure determinations revealed that the new compounds are isotypic to the known rare-earth fluoride borate Gd₂(BO₃)F₃. The new rare-earth fluoride borates crystallize in the monoclinic space group P2₁/c (Z = 8) with the lattice parameters a = 16.296(3), b = 6.197(2), c = 8.338(2) Å, β =93.58(3)° for Tb₂(BO₃)F₃, a = 16.225(3), b = 6.160(2), c = 8.307(2) Å, β =93.64(3)° for Dy₂(BO₃)F₃, and a = 16.189(3), b = 6.124(2), c = 8.282(2) Å, β =93.69(3)° for Ho₂(BO₃)F₃. The four crystallographically different rare-earth cations (CN = 9) are surrounded by oxygen and fluoride anions. All boron atoms form isolated trigonal-planar [BO₃]³⁻ groups. The six crystallographically different fluoride anions are in a nearly planar coordination by three rare-earth cations.

Key words: High Pressure, Lanthanoides, Fluoride, Borate, Crystal Structure

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