Metal phosphides have been used as rodenticides. A mixture of food and zinc phosphide is left where the rodents can eat it. The acid in the digestive system of the rodent reacts with the phosphide to generate the toxic phosphine gas. This method of vermin control has possible use in places where rodents immune to many of the common poisons have appeared. Other pesticides similar to zinc phosphide are aluminium phosphide and calcium phosphide.
Zinc phosphide is typically added to rodent baits in amount of around 0.75-2%. The baits have strong, pungent garlic-like odor characteristic for phosphine liberated by hydrolysis. The odor attracts rodents, but has a repulsive effect on other animals; birds, notably wild turkeys, are not sensitive to the smell. The baits have to contain sufficient amount of zinc phosphide in sufficiently attractive food in order to kill rodents in a single serving; a sublethal dose may cause aversion towards zinc-phosphide baits encountered by surviving rodents in the future.
Rodenticide-grade zinc phosphide usually comes as a black powder containing 75% of zinc phosphide and 25% of antimony potassium tartrate, an emetic to cause vomiting if the material is accidentally ingested by humans or domestic animals. However, it is still effective against rats, mice, guinea pigs and rabbits, all of which do not have a vomiting reflex.
Zinc phosphide can be prepared by the reaction of zinc with phosphorus:
Occupational Phosphine Gas Poisoning at Veterinary Hospitals from Dogs that Ingested Zinc Phosphide - Michigan, Iowa, and Washington, 2006-2011
Apr 27, 2012; Zinc phosphide (Zn3?2) is a readily available roden ticide that, on contact with stomach acid and water, produces phosphine...
Occupational Phosphine Gas Poisoning at Veterinary Hospitals from Dogs That Ingested Zinc Phosphide-Michigan, Iowa, and Washington, 2006-2011
Apr 27, 2012; Zinc phosphide ([Zn.sub.3][P.sub.2]) is a readily available rodenticide that, on contact with stomach acid and water, produces...