Synthesis, Crystal Structure, and Magnetic Study of Na7Sr2Fe7F32

✍ Scribed by A. Hemon-Ribaud; J.M. Greneche; G. Courbion

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 419 KB
• Volume: 112
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1994.1269

✦ Synopsis

(\mathrm{Na}{7} \mathrm{Sr}{2} \mathrm{Fe}{7} \mathrm{~F}{32}) is orthorhombic (space group Fddd) with (a=) (10.372(3) \AA, b=10.805(3) \AA, c=44.98(2) \AA), and (Z=8). The structure was determined from single-crystal data using 1261 independent (X)-ray reflections, with reliability (R=0.036\left(R_{\mathrm{w}}=0.029\right)). Corner-sharing iron octahedra give rise to a three-dimensional

chains and (\left[\left.\mathrm{Fe}{5} \mathrm{~F}{26}\right|^{11}\right.) octahedra pentamers can be distinguished. (\mathrm{Na}{7} \mathrm{Sr}{2} \mathrm{Fe}{7} \mathrm{~F}{32}) clearly exhibits an atypic magnetic behavior evidenced from Mössbauer and magnetic measurements (\left(T_{c} \approx 35\right.) (\mathrm{K})). A competition between ferromagnetic and antiferromagnetic couplings is suggested in relation to a frustrated octahedra network. O 1994 Academic Press, Inc.