Charge density waves in the mixed valence two dimensional metal, K(3)Cu(8)S(6).

In order to study the physical properties of K(3)Cu(8)S(6), we have carefully defined the synthetic conditions for KCu (4)S(3), K(3)Cu(8)S(6) and KCu(3)S(2). K(3)Cu(8)S(6) is apparently a kinetic phase and must be trapped with a minimum amount of either KCu(4)S(3) or KCu(3)S(2). Magnetic susceptibility and electrical resistivity data display behavior typical of CDW systems. In view of the low-dimensional metallic nature of K(3) Cu(8)S(6) and preliminary X-ray data, a second order reversible transition at T(1)=153K has been identified as the onset of an incommensurate lattice. In the region of 50-60k, at first order transition with considerable hysteresis seems to be a structural transition to a commensurate superlattice state.