[1] Passing hydrogen sulfide through a suspension of powdered sulfur in a concentrated ammonia solution:[2][3] Ammonium sulfide forms yellow crystals, decomposing in water, of monoclinic system, space group P21/c, cell parameters a = 0.5427 nm, b = 1.6226 nm, c = 0.9430 nm, β = 105.31°, Z = 4.

[4] The compound can be stored under the mother liquor without air access.

When dry, it decomposes quickly in the air.

the compound emits sulfur intensively in water and melts in a sealed ampoule at 95 °C to form a red liquid.

The compound decomposes when stored in air or slightly heated:[5]