ANOMALOUS ELECTRICAL-CONDUCTIVITY OF THE POTASSIUM DEFICIENT LINEAR-CHAIN PLATINUM COMPOUND - K1.75PT(CN)4.1.5H20

Four probe single crystal dc conductivity, σ, has been measured for K1.75Pt (CN)4·1.5H2O for temperature 360K > T > 30K on crystals prepared via electrochemical growth, with σ (295K) {A figure is presented} 25-50 Ω-1cm-1. An anomalous behavior in σ (T) is reported with σ (T) nearly constant for T > 300K and 160K > T > 80K, and rapidly decreasing σ (T) observed for 300K > T > 160K and T < 80K. The data for 200K < T < 308K are analyzed in terms of a three-dimensional second order phase transition occurring at Tc = 308K. These results contrast sharply with those of the well studied K2Pt(CN)4X0.3·3H20 (X=Cl,Br). © 1979.