Protactinium(V) iodide is an inorganic compound, with the chemical formula of PaI5.

[2] It reacts with antimony trioxide in a vacuum at 150 °C to give the iodide oxides PaOI3 and PaO2I; it reacts with protactinium(V) bromide at 350 °C to obtain mixed halides PaBr3I2.

[2] It reacts with the monocarbide at 600 °C to give tetraiodide.

[3] Aristid von Grosse was able to produce pure metallic protactinium with the decomposition of protactinium(V) iodide.

[4][5] When heated at 300 °C for a long time, it decomposes and iodine is released:[1]