Cu3(CH3COO)4(OH)2·5H2O: A Novel Isolated Spin-1/2 Diamond Chain Compound Showing Possible Valence-Bond Condensation

A novel compound Cu3(CH3COO)4(OH)2·5H2O was obtained by a hydrothermal method with a special synthesis process. The crystal structure is found to exhibit a unique one-dimensional diamond chain along the c-axis. Magnetic measurements confirmed that this compound exhibits unusual magnetic behaviors of a possible valence-bond condensation state at low temperature, where the two-thirds of all spins are condensed into spin singlets and one-third of the spins still remain in the paramagnetic state.