The test with the sulfide ion must be conducted in the presence of dilute HCl.

It also contains sulfide ions.

A common motif features a four iron ions and four sulfide ions placed at the vertices of a cubane-type structure.

Thioacetamide was widely used in classical qualitative inorganic analysis as an in situ source for sulfide ions.

It does not always contains sulfide ions; sometimes it contains a mixture of sulfide and sulfur.

The latter results from sediment-borne anaerobic bacteria capable of reverting sulfate ions into sulfide ions.

One of the best-known thioamides is thioacetamide, which is used as a source of the sulfide ion and is a building block in heterocyclic chemistry.

So as more sulfide ion is made into H2S, the copper sulfide should dissolve.

The debris encourages anaerobic bacteria, which can revert sulfate ions into sulfide ions.