Structure Refinement and Magnetic Properties of C–Fe(PO3)3 Studied by Neutron Diffraction and Mössbauer Techniques

✍ Scribed by L.K. Elbouaanani; B. Malaman; R. Gérardin

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 418 KB
• Volume: 148
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1999.8479

✦ Synopsis

C+Fe(PO 3 ) 3 has been synthesized using H 3 PO 4 and Fe(NO 3 ) 3 ' 9H 2 O as starting compounds. Single crystals were grown under vacuum with a trace of FeCl 2 . Fe(PO 3 ) 3 crystallizes in the monoclinic space group Cc, with a ‫؍‬ 13.148(4) A s , b ‫؍‬ 19.076(2) A s , c ‫؍‬ 9.410(3) A s , ‫؍‬ 127.00(2)3, and Z ‫؍‬ 12. Its structure has been determined through direct methods and di4erence Fourier synthesis and has been re5ned to R ‫؍‬ 0.0405 (R W ‫؍‬ 0.047). Fe(PO 3 ) 3 belongs to a series of isotypic M(PO 3 ) 3 trimetaphosphates (M ‫؍‬ Al, V, Sc, In, Ti, Mo, Rh, Cr) which are characterized by a tridimensional network of isolated MO 6 octahedra connected through PO 4 tetrahedra. Fe(PO 3 ) 3 is antiferromagnetic below T N ‫؍‬ 10 K. The magnetic structure has been determinated by means of powder neutron di4raction: each iron atom is linked to six iron nearest neighbors of opposite spin, through six single Fe+O+P+O+Fe superexchange pathways. The moment direction lies in the (010) plane, making an angle of &323 with the a axis ( &4.4 B ). MoK ssbauer spectra are 5tted with two doublets and three sextuplets in the paramagnetic and the antiferromagnetic states, respectively. Their rather high isomer shifts are explained by the inductive e4ect.