NH4HS

Ammonium hydrosulfide, with the chemical formula NH4HS, is an inorganic compound also known as ammonium bisulfide or ammonium hydrogen sulfide. It is a salt formed from the reaction of ammonia (NH3) and hydrogen sulfide (H2S). In its pure form, ammonium hydrosulfide is a colorless crystalline solid. However, it is often encountered as an aqueous solution, which typically has a yellowish tint due to the presence of polysulfides.

Ammonium hydrosulfide is highly soluble in water. It is also soluble in alcohols. When heated, it decomposes into ammonia and hydrogen sulfide. This decomposition readily occurs even at room temperature, contributing to its characteristic pungent odor, often described as rotten egg-like. This odor is a key indicator of its presence.

The compound is primarily used in industrial applications. It is a reagent in the synthesis of various sulfur-containing organic compounds and is employed in the petroleum industry for the removal of sulfur from crude oil. It also finds use in the production of dyes and in photography. Due to the toxicity and flammability of both ammonia and hydrogen sulfide, ammonium hydrosulfide must be handled with care, ensuring adequate ventilation and avoiding contact with skin and eyes.