Electrical and thermal properties of the partially oxidized salt of the magnus green salt with the formula Pt6 (NH3)10Cl10(HSO4)4

Abstract

AbstractThe salt Pt6(NH3)10Cl10(HSO4)4(MGSPOS) with the average valence of Pt 2.33 was prepared in powder form by means of partial oxidization of [Pt(NH3)4][PtCl4](MGS) substituting HSO4− for 1/6 of both ligands NH3 and Cl−. The electrical conductivity σ has a maximum at about 230 K and a minimum at about 280 K. Therefore, the conductivity σ is semiconductive with the gap energy 0.04 eV below 230 K, and metallic in the sense of dσ/dT < 0 between 230 and 280 K, and again semiconductive above 280 K. The thermal analysis by DSC shows only on heating, three anomalies, G at ∼150 K, A at ∼ 200 K, and B at ∼250 K. The exothermic anomaly A succeeding to the weak anomaly G indicates that a glass transition takes place, and endothermic anomaly B corresponds to a structural transition. These two transitions may correspond to the two metal–semiconductor transitions found in the σ measurement. The ac calorimetry shows a specific heat anomaly also only on heating.