Synthesis, crystal structure and physical properties of NaMnFe(MoO4)3
Written by sctunisie no commentsIron molybdate NaMnFe(MoO4)3 has been synthesized by flux method and solid state reaction, and characterized by X-ray diffraction, magnetic susceptibility and ionic conductivity. This compound is isostructural with α-NaFe2 (MoO4)3 and crystallizes in the triclinic space group PĪ with the cell parameters: a = 6.963(3) Å, b = 6.998(1) Å, c = 11.169(2) Å, α = 79.88(1)°, β = 84.01(3)°, γ = 80.81(3)° and Z = 2. Its structure is built up from [Mn,Fe]2O10 units of edge-sharing [Mn,Fe]O6 octahedra which are linked to each other through the common corners of MoO4 tetrahedra. The resulting anionic three-dimensional framework leads to the formation of channels along the [101] direction, where the Na+ cations are located. The disordered distribution of iron and manganese in the same site is confirmed by bond valence calculation. Magnetic measurements show that this compound to be antiferromagnetic with Cm = 9.03 emu K/mol and θ = -65.5 K. Ionic conductivity results of the title compound reveal an activation energy Ea = 0.95 eV noticeably higher than Ea < 0.36 eV observed for NaMFe(MoO4)3 (M = Ni, Zn) . This disparity can be related to the difference between the structural characteristics of both kinds of compounds.
M. Mhiri, A. Badri, M.L. Lopez, C. Pico, M. Ben Amara
Iron molybdate; X-ray diffraction; Magnetic measurements; Ionic conductivity
Pages 158-167
