ChemInform Abstract: Mild Hydrothermal Synthesis, Crystal Structure, Thermal Behavior, Spectroscopic and Magnetic Properties of the (NH₄) [Fe(AsO₄)_1‐x(PO₄)_xF] (I) (x = 0.3, 0.6, 0.8) Series. Thermal Transformation of (NH₄) [Fe(AsO₄)_0.7(PO₄)_0.3F] into the Textural Porous Orthorhombic Fe(AsO₄)_0.7(PO₄)_0.3 (II).

Abstract

Iron I 7100 Mild Hydrothermal Synthesis, Crystal Structure, Thermal Behavior, Spectroscopic and Magnetic Properties of the (NH 4 )[Fe(AsO 4 ) 1-x (PO 4 ) x F] (I) (x = 0.3, 0.6, 0.8) Series. Thermal Transformation of (NH4)[Fe(AsO4)0.7(PO4)0.3F] into the Textural Porous Orthorhombic Fe(AsO4)0.7(PO4)0.3 (II). -Light-green single crystals of compounds (I) (orthorhombic space group Pna21 with Z = 8) are hydrothermally prepared from a mixture of Fe2(SO4)3, As2O5, H3PO4, HF, and NH4OH in H2O (autoclave, pH 3, 170°C, 5 d). Brown single crystals of (II) (orthorhombic, space group Imam, Z = 12) are obtained by heating single crystals of (NH4)[Fe(AsO4)0.7(PO4)0.3F] in air at 465°C for 40 h. Compounds (I) and (II) exhibit a related three-dimensional structure.The framework of (I) contains perpendicular chains formed by alternating Fe(2)O4F2 or Fe(1)O4F2 octahedra and As/P(2)O4 or As/P(1)O4 tetrahedra, respectively. (II) contains chains of alternating Fe (2)O 6 octahedra and As/P(2)O 4 tetrahedra. Magnetic measurements indicate the predominance of antiferromagnetic interactions in all the compounds. -(BERROCAL, T.; MESA*, J. L.; PIZARRO, J. L.; BAZAN, B.; LEZAMA, L.; ARRIORTUA, M. I.; ROJO, T.; J. Solid State Chem. 182 (2009) 4, 932-941;