The formation of the title compounds by reaction of copper with yellow ammonium sulphide solutions is investigated. The new compound Nh(4)Cu(4)S(3) is isotypic to KCu4S3 (space group P4/mmm, a = 3.907 Angstrom, c = 9.453 Angstrom) The topotactic decomposition of NH4Cu7S4 to digenite between 120-140 degrees C is studied and the crystallographic relations between educt and product are described. NH4Cu4S3 decomposes to a polycrystalline mixture of digenite and covellite between 190-210 degrees C.