The iron potassium diarsenate KFeAs{sub 2}O{sub 7} structural, electric and magnetic behaviors

Journal Article · Mon Oct 15 00:00:00 EDT 2007 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2007.08.011· OSTI ID:21049530

Ouerfelli, N ^[1]; Molinie, P ^[2]; Mazza, D ^[3]; Zid, M F; Driss, A ^[1]

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1. Laboratoire de Materiaux et Cristallochimie, Faculte des Sciences, El Manar, 2092 Tunis (Tunisia)
2. Institut des Materiaux Jean Rouxel, UMR CNRS 6502, 2 rue de la Houssiniere, BP 32229, 44322 Nantes Cedex 03 (France)
3. Dipartimento di Scienza dei Materiali e Ingegneria Chimica, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy)

Crystals of a new potassium iron (III) diarsenate (KFeAs{sub 2}O{sub 7}) have been grown and characterized by single crystal X-ray diffraction. It crystallizes in the triclinic space group P1-bar, with a=7.662(1) A, b=8.402(2) A, c=10.100(3) A, {alpha}=90.42(3){sup o}, {beta}=89.74(2){sup o}, {gamma}=106.39(2){sup o}, V=623.8(3) A{sup 3} and Z=4. The final agreement factors are R=0.0342, wR=0.0889, S(F{sup 2})=1.01; the structural model is validated by bond valence sum (BVS) and charge distribution (CD) methods. The structure consists of corner-sharing FeO{sub 6} octahedra and As{sub 2}O{sub 7} diarsenate groups, the three-dimensional framework delimits tunnels running along [0 1 0] direction where the potassium ions reside. The crystal structure of the title compound is different from that of the monoclinic KAlP{sub 2}O{sub 7} type but structural relationships exist between the frameworks. Impedance measurements (frequency/temperature ranges: 5-13,000 Hz/526-668 K) show KFeAs{sub 2}O{sub 7} an ionic conductor being the conductivity 2.76x10{sup -7} S cm{sup -1} at 568 K and E{sub a} is 0.47 eV. The BVS model suggests that the most probable potassium conduction pathway is along b-direction. Magnetic measurements reveal the Curie-Weiss type paramagnetic behavior over the range 30-300 K and ferromagnetic below 29.3 K. - Graphical abstract: Optimized trajectory for K1-K2-K1 jump as determined by BVS analysis.

• OSTI ID: 21049530
• Journal Information: Journal of Solid State Chemistry, Vol. 180, Issue 10; Other Information: DOI: 10.1016/j.jssc.2007.08.011; PII: S0022-4596(07)00328-3; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ARSENATES
CHARGE DISTRIBUTION
ELECTRIC CONDUCTORS
IMPEDANCE
IONIC CONDUCTIVITY
IRON COMPOUNDS
MAGNETIC PROPERTIES
MILLI EV RANGE
MONOCLINIC LATTICES
MONOCRYSTALS
PARAMAGNETISM
POTASSIUM COMPOUNDS
POTASSIUM IONS
SPACE GROUPS
STRUCTURAL MODELS
TEMPERATURE RANGE 0013-0065 K
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K
TRICLINIC LATTICES
X-RAY DIFFRACTION