fosfid

Fosfid, or phosphide, is a class of chemical compounds formed when phosphorus combines with a more electropositive element, typically a metal. Phosphides often exhibit ionic, covalent, or metallic bonding and have the general formula MxPy, where M is a metal and P is phosphorus. The oxidation state of phosphorus in many phosphides is −3, though bonding can vary.

Phosphides are divided into ionic metal phosphides (examples include calcium phosphide Ca3P2, zinc phosphide Zn3P2, and iron phosphide FeP) and covalent or semiconducting phosphide compounds (such as gallium phosphide GaP and indium phosphide InP). GaP and InP are important wide-bandgap semiconductors used in optoelectronics and high-speed electronics. Zn3P2 is used commercially as a rodenticide because its hydrolysis releases phosphine gas.

Production and preparation: Phosphides are typically prepared by direct reaction of phosphorus with a metal at elevated temperatures, or by reducing phosphates or other phosphorus sources with a suitable metal. Some phosphides also form during metallurgical processes and can be obtained as byproducts or components of alloys.

Properties and behavior: Phosphides are generally stable under inert conditions but can react with water or acids. Hydrolysis often releases phosphine (PH3), a toxic and flammable gas. They range from hard intermetallic solids to covalent semiconductors, with properties strongly influenced by composition and bonding.

Safety and applications: Handling phosphides requires appropriate ventilation and precautions against moisture exposure, as several phosphides release phosphine on contact with water. Applications span electronics (GaP, InP), pest control (Zn3P2), and catalytic or alloying contexts in metallurgy.