Ammonium hydrosulfide


Ammonium hydrosulfide is the chemical compound with the formula HS.

Composition

It is the salt derived from the ammonium cation and the hydrosulfide anion. The salt exists as colourless, water-soluble, micaceous crystals. On Earth the compound is encountered mainly as a solution, not as the solid, but NH4SH ice is believed to be a substantial component of the cloud decks of the gas-giant planets Jupiter and Saturn, with sulfur produced by its photolysis responsible for the color of some of those planets' clouds. It can be generated by mixing hydrogen sulfide and ammonia.

Preparation

Solutions of ammonium hydrosulfide can be prepared by passing hydrogen sulfide gas through concentrated ammonia solution. According to a detailed 1895 report, hydrogen sulfide reacts with concentrated aqueous ammonia solution at room temperature to give 2S·2NH4HS. When this species is cooled to 0 °C and treated with additional hydrogen sulfide, one obtains 2S·12NH4HS. An ice-cold solution of this substance kept at 0 °C and having hydrogen sulfide continually passed through it gives the hydrosulfide.
The common "stink bomb" consists of an aqueous solution of ammonium sulfide. The mixture easily converts to ammonia and hydrogen sulfide gases. This conversion illustrates the ease of the following equilibrium:
Ammonia and hydrogen sulfide each have a powerful and unpleasant smell.

"Ammonium sulfide"

Aqueous solutions of ammonium sulfide, also known as diammonium sulfide are commercially available, although the composition of these solutions is uncertain as they could consist of a mixture of ammonia and SH. Ammonium sulfide solutions are used occasionally in photographic developing, to apply patina to bronze, and in textile manufacturing. Also, due to its offensive smell, it is the active ingredient in a variety of pranks including the common stink bomb. It can be used as a selective reducing agent, where there are two nitro groups only one of them is selectively reduced.