Structural and magnetic phases of Fe(ND3)2PO4

Polycrystalline samples of Fe(ND3)2PO4 were prepared by means of a hydrothermal route and characterized using powder x-ray diffraction, scanning electron microscopy, chemical and thermal analysis, magnetic measurements, specific heat and neutron diffraction experiments. This material orders within an orthorhombic (Pnma space group) crystal structure at room temperature, but below 220 K the crystal structure changes towards a monoclinic P 21/n structure through a phase transition with almost no latent heat. Furthermore, the magnetic cell at 2 K is twice the size of the crystallographic cell observed at 80 K. The magnetic structure associated with the Fe(III) ions is thus commensurate with the crystal lattice having a propagation vector , the magnetic moments lying in the yz plane of the crystallographic cell.

[1]  N. Rajić.  Open-framework aluminophosphates: synthesis, characterization and transition metal modifications , 2005 .

[2]  C. Delacourt,et al.  Synthesis and Thermal Behavior of Crystalline Hydrated Iron(III) Phosphates of Interest as Positive Electrodes in Li Batteries , 2003 .

[3]  M. Whittingham,et al.  New iron(III) phosphate phases: crystal structure and electrochemical and magnetic properties. , 2002, Inorganic chemistry.

[4]  A. Espina,et al.  Magnetic properties of two hydrothermally synthesized iron(III) phosphates: Fe(NH3)2PO4 and Fe(NH4)(HPO4)2 , 2001 .

[5]  J. Rodríguez Fernández,et al.  Neutron scattering on the strongly correlated electron CeNi Cu system: from non-magnetic behaviour to long-range magnetic order , 2000 .

[6]  A. Choudhury,et al.  A new three-dimensional open-framework iron(III) phosphate, [C2N2H10][Fe2(HPO4)4] , 2000 .

[7]  A. Espina,et al.  Hydrothermal Synthesis and Structure of Fe(NH3)2PO4: A Novel Monophosphate. , 2000 .

[8]  A. Espina,et al.  Hydrothermal synthesis of iron(III) phosphates in the presence of urea , 2000 .

[9]  A. Espina,et al.  Hydrothermal Synthesis and Structure of Fe(NH(3))(2)PO(4): A Novel Monophosphate. , 1999, Inorganic chemistry.

[10]  Cheetham,et al.  Open-Framework Inorganic Materials. , 1999, Angewandte Chemie.

[11]  M. Ai.  Characteristics of iron phosphate as a catalyst for partial oxidation , 1999 .

[12]  M. Riou-Cavellec,et al.  Magnetic iron phosphates with an open framework , 1999 .

[13]  C. Marquina,et al.  MAGNETIC STRUCTURE OF GDCU THROUGH THE MARTENSITIC STRUCTURAL TRANSFORMATION : A NEUTRON-DIFFRACTION STUDY , 1999 .

[14]  R. Gurjar,et al.  TEMPERATURE EFFECTS IN THE HYPERFINE SPECTRUM OF THE D1 TRANSITION OF SODIUM , 1999 .

[15]  T. Hahn,et al.  International Tables for Crystallography: Volume A: Space-Group Symmetry , 1987 .

[16]  P. Moore.  Crystal chemistry of the basic iron phosphates , 1970 .

[17]  E. F. Bertaut,et al.  Representation analysis of magnetic structures , 1968 .