Phosphorus triiodide

Phosphorus triiodide is a chemical compound. It is made of one phosphorus and three iodine atoms. It contains phosphorus in its +3 oxidation state. Its chemical formula is PI3.

 Properties 
It is a red solid. It is very unstable and a powerful reducing agent. It reacts violently with water. The reaction with water makes phosphorous acid and hydrogen iodide. It is used in making chemicals. Some think that it is too unstable to be stored, but it can be stored and can be bought. 

 Preparation 
Phosphorus triiodide is made by reacting iodine with white phosphorus dissolved in carbon disulfide. It is dissolved in carbon disulfide because it does not dissolve in water. It can also be made by reacting phosphorus trichloride with hydrogen iodide or some other iodide.

 Uses 
It reacts with alcohols such as methanol to make "alkyl iodides" such as methyl iodide. Many times phosphorus triiodide is made in the reaction. The alkyl iodides are used in many chemical reactions.

 Related pages 
Phosphorus(III) oxide
Phosphorus compounds
Potassium iodide

Category:Phosphorus compounds
Category:Iodine compounds