Boron phospho-iodides

The compound BPI₂ is prepared by acting upon boron tri-iodide with phosphorus in carbon disulphide solution, and, in a carbon dioxide atmosphere, washing away the iodide of phosphorus simultaneously produced with a further quantity of carbon disulphide. It is a dark red solid which melts in vacuo at 190° to 200° and sublimes at higher temperatures. Chlorine, oxygen, and many metals attack it vigorously, and water immediately decomposes it, among the products being hydriodic, phosphorous, and boric acids. When heated to 160° in hydrogen it is reduced to the compound BPI, which sublimes in vacuo, forming orange-yellow crystals, and closely resembles the other phospho-iodide in properties.