The effect of lithium intercalation on the crystal structure and magnetic property of layered FeWO4Cl

LiFeWO4Cl has been prepared by reductive intercalation of lithium into FeWO4Cl. FeWO4Cl crystallize into a tetragonal system (space group P4/nmm) with cell dimensions of a = 6.677(5) Angstrom and c = 5.270(5) Angstrom, while lithium intercalation gives rise to the formation of a monoclinic phase (P2(1)/m) with cell dimensions of a = 7.050(0) Angstrom, b = 6.926(2) Angstrom, c = 5.043(0) Angstrom and beta = 92.54(2)degrees. Infrared (IR) spectroscopic analyses of FeWO4Cl show that the symmetry of the tetrahedral WO42- group in FeWO4Cl becomes reduced as the lithium intercalate into its two-dimensional lattice, indicating an alternately ordered lithium occupancy of half of the octahedral interlayer sites. The effective magnetic moments of FeWO4Cl and LiFeWO4Cl were estimated to be 5.95 and 5.10 B.M., respectively, which can be attributed to the selective reduction of a high-spin ferric ion to a high-spin ferrons one upon lithium intercalation. It was also found that the two-dimensional magnetic property of FeWO4Cl was changed to a three-dimensional one in LiFeWO4Cl owing to the c-axis contraction.