La4B14O27: Ein Lanthan‐ultra‐Oxoborat mit Raumnetzstruktur |
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Authors: | Tanja Nikelski Marion C Schäfer Thomas Schleid Prof Dr |
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Institution: | Stuttgart, Institut für Anorganische Chemie der Universit?t |
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Abstract: | La4B14O27: A Lanthanum ultra‐Oxoborate with a Framework Structure Single crystals of La4B14O27 could be synthesized by the reaction of La2O3, LaCl3 and B2O3 with an access of CsCl as fluxing agent in gastightly sealed platinum ampoules within twenty days at 710 °C and appear as colourless, transparent and waterresistant platelets. The new lanthanum oxoborate La4B14O27 (monoclinic, C2/c; a = 1120.84(9), b = 641.98(6), c = 2537.2(2) pm, β = 100.125(8)°; Z = 4) is built of a three‐dimensional boron‐oxygen framework containing seven crystallographically different boron atoms. Four of these B3+ cations are surrounded by four O2? anions tetrahedrally, whereas the other three have only three oxygen neighbours with nearly plane triangular coordination figures. Three of the BO4]5? tetrahedra form B3O9]9? rings by cyclic vertex‐condensation, which are further linked via BO3]3? units to infinite layers. Two of these layers connect via one B2O7]8? unit of two corner‐shared BO4]5? tetrahedra to double layers, which themselves build up a three‐dimensional framework together with chains consisting of two BO4]5? tetrahedra and one BO3]3? triangle. One of the two crystallographically independent La3+ cations (La1) is surrounded by ten O2? anions and resides within the oxoborate double layers. (La2)3+ shows a (8+2)‐fold coordination of O2? anions and occupies channels along the 110] direction. |
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Keywords: | Lanthanum Oxoborates Synthesis Crystal structure |
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