کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1331470 979005 2007 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
The iron potassium diarsenate KFeAs2O7 structural, electric and magnetic behaviors
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی معدنی
پیش نمایش صفحه اول مقاله
The iron potassium diarsenate KFeAs2O7 structural, electric and magnetic behaviors
چکیده انگلیسی

Crystals of a new potassium iron (III) diarsenate (KFeAs2O7) have been grown and characterized by single crystal X-ray diffraction. It crystallizes in the triclinic space group P1¯, with a=7.662(1) Å, b=8.402(2) Å, c=10.100(3) Å, α=90.42(3)°, β=89.74(2)°, γ=106.39(2)°, V=623.8(3) Å3 and Z=4. The final agreement factors are R=0.0342, wR=0.0889, S(F2)=1.01; the structural model is validated by bond valence sum (BVS) and charge distribution (CD) methods. The structure consists of corner-sharing FeO6 octahedra and As2O7 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 KAlP2O7 type but structural relationships exist between the frameworks. Impedance measurements (frequency/temperature ranges: 5–13,000 Hz/526–668 K) show KFeAs2O7 an ionic conductor being the conductivity 2.76×10−7 S cm−1 at 568 K and Ea 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.

Optimized trajectory for K1–K2–K1 jump as determined by BVS analysis.Figure optionsDownload as PowerPoint slide

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Solid State Chemistry - Volume 180, Issue 10, October 2007, Pages 2942–2949
نویسندگان
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