La3 B6 O13 (OH): The First Acentric High-Pressure Borate Displaying Edge-Sharing BO4 Tetrahedra

Birgit Fuchs; Gunter Heymann; Xuefei Wang; Abudukadi Tudi; Lkhamsuren Bayarjargal; Renée Siegel; Adrian Schmutzler; Jürgen Senker; Bastian Joachim-Mrosko; Andreas Saxer; Zhihua Yang; Shilie Pan; Hubert Huppertz

doi:10.1002/chem.201905419

La₃ B₆ O₁₃ (OH): The First Acentric High-Pressure Borate Displaying Edge-Sharing BO₄ Tetrahedra

Chemistry. 2020 May 26;26(30):6851-6861. doi: 10.1002/chem.201905419. Epub 2020 May 20.

Authors

Affiliations

¹ Institut für Allgemeine, Anorganische und Theoretische Chemie, Universität Innsbruck, Innrain 80-82, 6020, Innsbruck, Austria.
² CAS Key Laboratory of Functional Materials, and Devices for Special Environment, Xinjiang Technical Institute of Physics & Chemistry, CAS, Xinjiang Key Laboratory of Electronic Information Materials and Devices, 40-1 South Beijing Road, 830011, Urumqi, P. R. China.
³ Institut für Geowissenschaften, Goethe-Universität Frankfurt am Main, Altenhöferallee 1, 60438, Frankfurt am Main, Germany.
⁴ Inorganic Chemistry III and Northern Bavarian NMR Center, University of Bayreuth, Universitätsstraße 30, 95447, Bayreuth, Germany.
⁵ Institut für Mineralogie und Petrographie, Universität Innsbruck, Innrain 52, 6020, Innsbruck, Austria.
⁶ Institut für Konstruktion und Materialwissenschaften, Universität Innsbruck, Technikerstraße 13, 6020, Innsbruck, Austria.

Abstract

La₃ B₆ O₁₃ (OH) was obtained by a high-pressure/high-temperature experiment at 6 GPa and 1673 K. The compound crystallizes in the space group P2₁ (no. 4) with the lattice parameters a=4.785(2), b=12.880(4), c=7.433(3) Å, and β=90.36(10)°, and is built up of corner- as well as edge-sharing BO₄ tetrahedra. It represents the first acentric high-pressure borate containing these B₂ O₆ entities. The compound develops borate layers of "sechser"-rings with the La³⁺ cations positioned between the layers. Single-crystal and powder X-ray diffraction, vibrational and MAS NMR spectroscopy, second-harmonic generation (SHG) and thermoanalytical measurements, as well as computational methods were used to affirm the proposed structure and the B₂ O₆ entities.

Keywords: NMR spectroscopy; high-pressure chemistry; lanthanum borate; nonlinear optics; vibrational spectroscopy.