Electrical and thermal properties of the partially oxidized salt of the magnus green salt with the formula Pt 6 (NH 3 ) 10 Cl 10 (HSO 4 ) 4

The salt Pt 6 (NH 3 ) 10 Cl 10 (HSO 4 ) 4 (MGSPOS) with the average valence of Pt 2.33 was prepared in powder form by means of partial oxidization of [Pt(NH 3 ) 4 ][PtCl 4 ](MGS) substituting HSO 4 − for 1/6 of both ligands NH 3 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 d σ/ 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.