Phosphine is a chemical compound. Its chemical name is phosphorus hydride. Its chemical formula is PH₃. It is also called phosphane and phosphamine. It contains phosphide and hydrogen ions.

It is a colorless, flammable gas. It is highly toxic; it can easily kill, even when concentration levels are low. It smells like fish. It can ignite without a spark. When it burns, it makes a white cloud of phosphorus(V) oxide, which is irritating.

It is made when hypophosphites and phosphites are heated. It is also made when white phosphorus reacts with warm alkali.

The gas is used for pest control. It is also used in making semiconductors.

• Ammonia