It is a liquid that evaporates easily. When it is exposed to light, it turns purple because of iodine. This can be stopped by keeping it with copper. It breaks down when heated to make carbon dioxide, carbon monoxide, and hydrogen iodide.
It is made by reacting iodine, red phosphorus, and methanol all at the same time. Phosphorus(III) iodide is formed during the reaction. Another way to make it is to react methanol with potassium iodide and some sulfuric acid.