A One-Dimensional Metal Embedded in Salt Matrices: Synthesis, Modulated Crystal Structures, Electrical Conductivity, and Chemical Bonding of (1)(infinity) PdBi6 (Bi,Sn)(1-delta)Br5-delta,
2009 (English)In: Zeitschrift für Anorganische und Allgemeines Chemie, ISSN 0044-2313, E-ISSN 1521-3749, Vol. 635, no 12, 1979-1985 p.Article in journal (Refereed) Published
The metal-rich compounds (1)(infinity)[PdBi6][(Bi,Sn)(1-delta)Br5-delta,] with delta(1) = 2/13, delta(1)' = 5/26, or delta(2) = delta(2)' = 2/12 were synthesized from Bi2Pd, BiBr3, and Sn at 300 degrees C. The crystal structures contain intermetallic rods (1)(infinity)[Pd@Bi2/1Bi8/2](2.5+) embedded in salt-like matrices, which consist of groups of bromido-bismuthate(III)-stannate(II) octahedra [(Bi,Sn)(n)Br4n+2](m-) (n = 2, 3) and isolated Br- ions. Metrical incompatibilities of the two subsystems in the crystalline metal-salt hybrid result in non-stoichiometry of the salt pan associated with complex superstructures. The average structure is described in the orthorhombic space group Pmmm with a approximate to 408 pm, b approximate to 2263 pm, c approximate to 849 pm. It feigns statistical distribution of vacancies and orientational disorder of the concatenated octahedra. By choosing the modulation vectors q(i) = 2/ta* + 1/2b* + 1/2c* with t(1) = 13 or t(2) = 12, the additional weak reflections of the diffraction patterns are indexed. Ordered structure models are achieved in the [3+1]-dimensional superspace group Pmmm(alpha 1/21/2)000. Metallic conductivity along , i.e. the direction of the (1)(infinity)[Pd@Bi2/1Bi8/2](2.5+) rods, was determined for a single-crystal. One-dimensional band structure calculations reveal Bi p-bands crossing the Fermi level for formula charges higher than 2+. The electron localization indicator (ELI) indicates two-center Bi-Bi bonds as well as multi-center bonds inside the metallic part, whereas the bismuth l one-pairs point towards the non-conducting part of the structure.
Place, publisher, year, edition, pages
2009. Vol. 635, no 12, 1979-1985 p.
IdentifiersURN: urn:nbn:se:kth:diva-18939DOI: 10.1002/zaac.200900191ISI: 000271575500036ScopusID: 2-s2.0-70350338742OAI: oai:DiVA.org:kth-18939DiVA: diva2:336986
QC 201005252010-08-052010-08-052011-01-17Bibliographically approved