Synthesis, characterization, and electronic structure of KV3Te3O0.42

Eric J. Wu, Michael A. Pell, Hugh S. Genin, James A. Ibers*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

KV3Te3O0.42 has been synthesized at 1173 K and its structure has been determined by single-crystal X-ray methods. The compound crystallizes in space group C26h-P63/m of the hexagonal system with two formula units in a cell of dimensions a=9.62(2) Å, c=4.48(1) Å, V=359(1) Å3 (T=113 K). The formula KV3Te3Ox, x=0.42(4), is derived from the X-ray data; combustion analysis for oxygen gives 0.18<x<0.37; EDS experiments suggest x=0; band structure calculations favor x>0. The evidence for the presence of oxygen is strong, but not conclusive. For KV3Te3O0.42, Rw(F2o)=0.080 for 358 observations and 19 variables, and R(F)=0.034 for 308 reflections having F2o>2σ(F2o). KV3Te3O0.42 crystallizes with the TlFe3Te3 structure, modified by addition of interstitial oxygen atoms at the centers of V6 octahedra. The structure comprises 1[V6Te6O2- x] chains along c. The chains are separated by K+ cations that are coordinated to nine Te atoms in a tricapped trigonal prismatic arrangement. Two-probe resistivity measurements along the needle axis (c) show that KV3Te3O0.42 has a conductivity of 2.4(1)X10-2 Ω-1 cm-1 at room temperature. The magnetic susceptibility of KV3Te3O0.42 may be fit to the modified Curie-Weiss expression χ=χ0 + C/(T+θ) with χ0 = 1-08(6)X10-3 emu mol-1, C=2.24(4)X10-2 emu K mol-1, and θ=-4.3(2) K, with μeff (300 K)=1.66(4) μB for each KV3Te3O0.42 unit. Extended Hückel band structure calculations on several structural models reveal that optimum metal-metal bonding is achieved with one oxygen atom in every second vanadium octahedron. From the band structure, a Peierls' distortion is predicted that may account for the semiconducting behavior.

Original languageEnglish (US)
Pages (from-to)123-129
Number of pages7
JournalJournal of Alloys and Compounds
Volume278
Issue number1-2
DOIs
StatePublished - Aug 1 1998

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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