Structure and Magnetic Properties of a New Oxohalogenide Compound Ba 7 CoV 6 O 21 Cl 4

A new oxohalogenide compound Ba7CoV6O21Cl4 was synthesized by a conventional high-temperature solid state reaction. The title compound is found to crystallize in the orthorhombic system of space group Cmcm with a = 16.726(4), b = 10.568(3), c = 14.808(4) A, V = 2617.4(12) A, Z = 2, Mr = 1803.68, Dc = 3.411 g/cm, μ = 11.396 mm, F(000) = 3172, the final R = 0.0314 and wR = 0.0750 for 1531 observed reflections with I > 2σ(I). Co ions are coordinated by four O and two Cl atoms, forming a CoO4Cl2 octahedron, while V atoms are tetrahedrally coordinated, forming (V2O7) groups. The structure of Ba7CoV6O21Cl4 exhibits a pseudo-onedimensional chain running along the c-axis. Magnetic measurements confirm that Ba7CoV6O21Cl4 shows a paramagnetic behavior down to 2 K. Keyword: oxohalogenide, crystal structure, solid-state reaction, magnetism; DOI: 10.14102/j.cnki.0254-5861.2011-0711