Na2B2S5 and Li2B2S5: Two Novel Perthioborates with Planar 1,2,4-Trithia-3,5-Diborolane Rings |
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Authors: | Christoph Jansen,J rn Kü per,Bernt Krebs |
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Affiliation: | Christoph Jansen,Jörn Küper,Bernt Krebs |
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Abstract: | For the first time perthioborates with trigonal planar coordination of boron were prepared. Na2B2S5 (Pnma, a = 12.545(2) Å, b = 7.441(1) Å, c = 8.271(1) Å, Z = 4) and Li2B2S5 (Cmcm, a = 15.864(1) Å, b = 6.433(1) Å, c = 6.862(1) Å, Z = 4) were obtained by reaction of the metal sulfides with stoichiometric amounts of boron and an excess of sulfur (effective molar ratio M:B:S = 1:1:4) at 600°C (650°C) and subsequent annealing. The non-isotypic structures contain exactly planar [B2S5]2? groups consisting of five-membered B2S3 rings with one additional exocyclic sulfur on each of the boron atoms. The alkaline metal cations are four-coordinate (lithium) and (four + four)-coordinate (sodium) respectively. |
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Keywords: | Lithium perthioborate sodium perthioborate synthesis crystal structure |
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