Crystal Structure Refinement and Bonding Patterns of CrB4: A Boron-Rich Boride with a Framework of Tetrahedrally Coordinated B Atoms

Crystals of chromium tetraboride, a recently proposed candidate superhard material, have been grown for the first time to allow for a first structure refinement of the compound [orthorhombic, space group Immm (No. 71), a = 474.82(8) pm, b = 548.56(8) pm, and c = 287.17(4) pm, R value (all data) = 0....

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Bibliographic Details
Published in:Inorganic chemistry 2011-11, Vol.50 (21), p.10540-10542
Main Authors: Knappschneider, Arno, Litterscheid, Christian, Kurzman, Joshua, Seshadri, Ram, Albert, Barbara
Format: Article
Language:English
Online Access:Get full text
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Summary:Crystals of chromium tetraboride, a recently proposed candidate superhard material, have been grown for the first time to allow for a first structure refinement of the compound [orthorhombic, space group Immm (No. 71), a = 474.82(8) pm, b = 548.56(8) pm, and c = 287.17(4) pm, R value (all data) = 0.018]. The previously proposed structure model is confirmed, and accurate interatomic distances are presented for the first time. First-principles electronic structure calculations emphasize the unique framework of three-dimensionally linked B atoms that are tetrahedrally coordinated and carry a slightly negative charge. All B–B bonding is of the 2-center 2-electron type. CrB4 is metallic with a pseudogap at the Fermi level.
ISSN:0020-1669
1520-510X
DOI:10.1021/ic2018083