Zr{sub 2}Ir{sub 6}B with an eightfold superstructure of the cubic perovskite-like boride ZrIr{sub 3}B{sub 0.5}: Synthesis, crystal structure and bonding analysis

Journal Article · Thu Apr 15 00:00:00 EDT 2010 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2010.01.026· OSTI ID:21372553

Hermus, Martin ^[1]

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1. Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52056 Aachen (Germany)

Single phase powder samples and single crystals of Zr{sub 2}Ir{sub 6}B were successfully synthesized by arc-melting the elements in a water-cooled copper crucible under an argon atmosphere. Superstructure reflections were observed both on powder and on single crystal diffraction data, leading to an eightfold superstructure of ZrIr{sub 3}B{sub x} phase. The new phase, which has a metallic luster, crystallizes in space group Fm3-barm (no. 225) with the lattice parameters a=7.9903(4) A, V=510.14(4) A{sup 3}. Its crystal structure was refined on the basis of powder as well as single crystal data. The single crystal refinement converged to R{sub 1}=0.0239 and wR{sub 2}=0.0624 for all 88 unique reflections and 6 parameters. Zr{sub 2}Ir{sub 6}B is isotypic to Ti{sub 2}Rh{sub 6}B and its structure can be described as a defect double perovskite, A{sub 2}BB'O{sub 6}, where the A site is occupied by zirconium, the B site by boron, the O site by iridium but the B' site is vacant, leading to the formation of empty and boron-filled octahedral Ir{sub 6} clusters. According to the result of tight-binding electronic structure calculations, Ir-B and Ir-Zr interactions are mainly responsible for the structural stability of the phase. According to COHP bonding analysis, the strongest bonding occurs for the Ir-B contacts, and the Ir-Ir bonding within the empty clusters is two times stronger than that in the BIr{sub 6} octahedra. - Graphical abstract: Zr{sub 2}Ir{sub 6}B crystallizes with an eightfold superstructure of the already reported simple cubic perovskite ZrIr{sub 3}B{sub x}. According to the result of tight-binding electronic structure calculations, Ir-B and Ir-Zr interactions are mainly responsible for its structural stability, and the Ir-Ir bonding within the empty Ir{sub 6} clusters is two times stronger than that in the BIr{sub 6} octahedra.

• OSTI ID: 21372553
• Journal Information: Journal of Solid State Chemistry, Vol. 183, Issue 4; Other Information: DOI: 10.1016/j.jssc.2010.01.026; PII: S0022-4596(10)00040-X; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ARGON
CUBIC LATTICES
ELECTRONIC STRUCTURE
IRIDIUM BORIDES
LATTICE PARAMETERS
MELTING
MONOCRYSTALS
PEROVSKITE
SPACE GROUPS
STABILITY
SYNTHESIS
ZIRCONIUM BORIDES
BORIDES
BORON COMPOUNDS
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CRYSTALS
ELEMENTS
FLUIDS
GASES
IRIDIUM COMPOUNDS
MINERALS
NONMETALS
OXIDE MINERALS
PEROVSKITES
PHASE TRANSFORMATIONS
RARE GASES
REFRACTORY METAL COMPOUNDS
SYMMETRY GROUPS
TRANSITION ELEMENT COMPOUNDS
ZIRCONIUM COMPOUNDS