Polymorphic transformation in nanocrystalline silver sulfide

Resumo

The α-Ag₂S acanthite–β-Ag₂S argentite phase transformation in nanocrystalline silver sulfide has been studied in situ for the first time using high-temperature X-ray diffraction and scanning electron microscopy. The formation of argentite has been proved by differential thermal analysis. The acanthite–argentite transformation occurs at a temperature of ∼449–450 K, and its enthalpy is ∼3.7–3.9 kJ mol^–1. The thermal expansion coefficients of acanthite and argentite have been estimated.