Z. Naturforsch. 2014, 69b, 1260 – 1268
The High-pressure Thallium Triborate HP-TlB3O5
Gerhard Sohr1, Lukas Perfler2 and Hubert Huppertz1
1 Institut für Allgemeine, Anorganische und Theoretische Chemie, Leopold-Franzens-Universität Innsbruck, Innrain 80–82, A-6020 Innsbruck, Austria
2 Institut für Mineralogie und Petrographie, Leopold-Franzens-Universität Innsbruck, Innrain 52f, A-6020 Innsbruck, Austria
Reprint requests to H. Huppertz. E-mail: Hubert.Huppertz@uibk.ac.at
Received June 2, 2014 / published online December 19, 2014
Dedicated to Professor Hubert Schmidbaur on the occasion of his 80th birthday
The thallium triborate HP-TlB3O5 (HP = high-pressure) was synthesized in a Walker-type multianvil apparatus under high-pressure/high-temperature conditions of 6 GPa and 1400°C. A mixture of thallium carbonate Tl2CO3 and boric acid H3BO3 initially heated at 850°C under ambient-pressure conditions was used as a precursor for the high-pressure experiment. Single-crystal X-ray diffraction data revealed that HP-TlB3O5 is isotypic to HP-M′B3O5 (M′ = K, Rb). Furthermore the B–O network is identical to the substitutional variants HP-M′′B3O5 [M′′ = Cs1−x(H3O)x (x = 0.5–0.7), NH4]. HP-TlB3O5 crystallizes with eight formula units (Z = 8) in the monoclinic space group C2/c (no. 15). The lattice parameters are a = 996.3(2), b = 884.0(2), c = 913.1(2) pm, β = 103.3(1), and V = 782.5(3) Å3. Trigonal-planar BO3 groups, corner-sharing BO4 tetrahedra, and B2O6 groups consisting of two edge-sharing BO4 tetrahedra are present in the structure, forming a three-dimensional network. The thallium ions are located in channels of the boron-oxygen network being tenfold coordinated by oxygen atoms and do not show any lone pair effect at all. IR and Raman spectroscopic investigations were performed on single crystals of the compound.
Key words: High-pressure, Borate, Crystal Structure, Lone Pair, Thallium
Full-text PDF