phosphine(redirected from phosphoniums)
Also found in: Dictionary, Thesaurus, Encyclopedia.
A colorless poisonous war gas (PH3) with a characteristic garliclike odor; also the active agent in some rodenticides; formed in small quantities in the putrefaction of organic matter containing phosphorus.
1. PH3, a toxic war gas called hydrogen phosphide.
2. a coal tar dye; called Philadelphia yellow.