Strukturelle Untersuchungen an Cs2[B12H12] |
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Authors: | Ioannis Tiritiris,Thomas Schleid,Klaus Mü ller,Wilhelm Preetz |
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Abstract: | Structural Investigations on Cs2[B12H12] The crystal structure of Cs2[B12H12] has been determined from X‐ray single‐crystal data collected at room temperature. Dicesium dodecahydro‐closo‐dodecaborate crystallizes as colourless, face‐rich crystals (cubic, Fm 3; a = 1128.12(7) pm; Z = 4). Its synthesis is based on the reaction of Na[BH4] with BF3(O(C2H5)2) via the decomposition of Na[B3H8] in boiling diglyme, followed by subsequent separations, precipitations (with aqueous CsOH solution) and recrystallizations. The crystal structure is best described as anti‐CaF2‐type arrangement with the Cs+ cations in all tetrahedral interstices of the cubic closest‐packed host lattice of the icosahedral [B12H12]2–‐cluster dianions. The intramolecular bond lengths are in the range usually found in closo‐hydroborates: 178 pm for the B–B and 112 pm for the B–H distance. Twelve hydrogen atoms belonging to four [B12H12]2– icosahedra provide an almost perfect cuboctahedral coordination sphere to the Cs+ cations, and their distance of 313 pm (12 ×) attests for the salt‐like character of Cs2[B12H12] according to {(Cs+)2([B12H12]2–)}. The 11B{1H}‐NMR data in aqueous (D2O) solution are δ = –12,70 ppm (1JB–H = 125 Hz), and δ = –15,7 ppm (linewidth: δν1/2 = 295 Hz) for the solid state 11B‐MAS‐NMR. |
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Keywords: | Boron Dodecahydro‐closo‐dodecaborates Crystal structure NMR (11B) spectroscopy |
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