Characteristic

Silver sulfide is the inorganic compound with the formula Ag₂S. A dense black solid, it is the only sulfide of silver. 

Chemical formula：Ag₂S

Molar mass： 247.80 g·mol⁻¹

Appearance： Grayish-black crystal

Odor： Odorless

Density： 7.234 g/cm3 (25 °C)   7.12 g/cm3 (117 °C)

Melting point： 836 °C (1,537 °F; 1,109 K)

Solubility in water：6.21·10⁻¹⁵ g/L (25 °C)

Solubility product (Ksp)：6.31·10⁻⁵⁰

Solubility： Soluble in aq. HCN, aq. citric acid with KNO3

                    Insoluble in acids, alkalies, aqueous ammoniums

Crystal structure：Cubic, cI8 (α-form)   Monoclinic, mP12 (β-form)   Cubic, cF12 (γ-form)

Application

It is useful as a photosensitizer in photography. It constitutes the tarnish that forms over time on silverware and other silver objects.

Silver Sulfide-MSDS.pdf