Crystal structure and electronic states of the low-dimensional system

Abstract

The crystal structure of has been determined by x-ray four-circle diffraction. The crystal data at 296 K indicate an orthorhombic structure with space group Cmcm; a = 3.692(1) Å, b = 9.971(1) Å, c = 11.018(1) Å, and Z = 4. Full-matrix least-squares refinement gives the residual factors R = 0.038 and for 976 independent reflections with the internal consistency . The V zigzag chains are formed along the a-axis by sharing edges and corners of pyramids, and the corner-sharing linkage between the chains along the c-axis leads to quasi-two-dimensional layers which stack alternately along the b-axis. The electronic states have been explored through magnetization and EPR measurements. A Curie-Weiss-type paramagnetism with is present above 300 K, while at low temperatures, short-range-order effects appear with a critical contribution of the EPR linewidth. This is clearly different from the spin-gap properties of , which may be attributed to a significant change in the path of superexchange interaction between the chains.