Barium sulfide

Barium sulfide is a chemical compound. Its chemical formula is BaS. It contains barium and sulfide ions.
Properties.
Barium sulfide is colorless when pure. It can get colored when it is not pure. It reacts slowly with water to make barium hydroxide and hydrogen sulfide. It reacts with acids to make a barium salt and hydrogen sulfide, too.
Preparation.
It is made by reduction of barium sulfate with carbon at a high temperature. 
Uses.
It is used to make barium compounds from barium ore.
Safety.
Barium sulfide looks very similar to barium sulfate. Barium sulfate is not toxic, while barium sulfide is very toxic. Barium sulfide dissolves in water to make toxic hydrogen sulfide and toxic barium hydroxide. If someone is fed barium sulfide, it would kill them.