Protactinium tetraiodide is a binary inorganic compound of protactinium metal and iodine with the chemical formula PaI4.

[1][2] Protactinium tetraiodide can be prepared by reducing the pentaiodide with aluminum at about 400 °C:[3] Also, a reaction of hydrogen reduction of protactinium(V) iodide at 400 °C:[4] The compound forms black or dark green crystals.

[4] The structure is not known.

[5] The compound is oxidized by antimony trioxide when heated in a vacuum:[6] The compound also reacts with quartz when heated:[dubious – discuss]