Ammonium sulfide, chemical formula (NH4)2S. It is usually used in an aqueous solution, the solid is unstable, and will form polysulfides and thiosulfates when exposed to air. Can be used for photographic color development agent.

Appearance and properties: Yellow to orange smoking liquid

Density: 1 g/mL at 25 °C

Boiling point: 40 °C

Melting point: -18oC

Flash point: 90 °F

Refractive index: n20/D 1.467

Stability: Stable. Pure material is highly flammable - note wide explosion limits. Incompatible with strong oxidizing agents,  strong acids, copper, brass, bronze, strong bases, zinc, aluminium.

Storage conditions: the warehouse is ventilated and dry at low temperature, and stored separately from the acid

Usage

Nitrate fiber denitrification agent. Sulfides are removed from calcium and magnesium assays. Microanalysis of thallium. Photographic development. Used as an analytical reagent, such as a sulfide precipitator. It is also used as a reagent for the detection of various inorganic ions by thin layer chromatography.