ELECTRICAL CONDUCTIVITIES OF CATION DEFICIENT ANALOGS OF KCP - M1.75[PT(CN) 4].1.5H2O, M=K,RB

Electrical conductivity studies of the quasi one-dimensional metals M1.75[Pt(CN)4]·1.5H2O, M(def)TCP, with M=K, Rb show an unexpected behaviour within the class of KCP-type conductors. At low temperatures the conduction is activated with the gap Δ=55 meV (Eg=2Δ), and at T=50 kelvin a transition to a metallic state appears to take place. However, above T=200 kelvin, the conductivity becomes strongly temperature dependent, which we ascribe to the onset of rotation of the crystal water. Our interpretation is in agreement with recent Raman scattering experiments. © 1979.