LAUSR

In order to obtain a Ba analogue of the Mott insulator SrCu(OH)3Cl, a new structure-type compound BaCu(OH)3Cl has been synthesized by a hydrothermal method. The crystal structure of the title compound consists of an undulating [BaCl]+ layer and a plane of [Cu(OH)3]− single chains, stacking alternately along the c-axis. The [Cu(OH)3]− single chains composed of corner-sharing [CuO4] squares are isolated in the plane and connected by barium atoms from the next layers. The Cu2+ ions from the isolated chains form a two-dimensional chessboard layer of CuO2, similar to those in the quasi-one-dimensional Mott insulator Sr2CuO3 and the superconductor Sr2CuO3+δ. The chessboard layers of CuO2 have been proposed to be responsible for high-temperature superconductivity. Magnetic susceptibility measurements indicate that the title compound has a nearly ideal spin-1/2 antiferromagnetic Heisenberg chain (spin Hamiltonian H = J∑SiSi+1) with an intrachain coupling constant J/kB = 135.7(6) K. The title compound as a quasi-one-dimensional Mott insulator with the characteristic chessboard layer of CuO2 provides a new prototype for doped derivatives in the search for high-temperature superconductors.