In Situ and Ex Situ Studies of Tetrammineplatinum(II) Chromate Thermolysis

Comparative analysis have shown that the thermolysis of complex salt [Pt(NH₃)₄]CrO₄ in synthetic air atmosphere under in situ and ex situ conditions proceeds in different routes. In contrast to in situ experiment, ex situ decomposition leads to formation of intermediate PtCrO₂ phase with delafossite structure. Final decomposition product is a homogeneous mixture of platinum metal and chromium(III) oxide. Complex [Pt(NH₃)₄]CrO₄ has been shown to have negative volumetric coefficient of thermal expansion in the temperature range 30–200°C (–1.9 × 10^–5 1/K). Ex situ experiments have shown stability of the complex on consecutive cyclic heating to 200°C and cooling to ambient temperature