Tungsten(IV) iodide is a binary inorganic compound of tungsten metal and iodine with the chemical formula WI4.

[1][2][3] Reaction of tungsten(VI) chloride with hydrochloric acid:[4] Reaction of tungsten(IV) chloride with hydrochloric acid: Tungsten(IV) iodide forms black crystals of the triclinic crystal system.

[5] Insoluble in cold water, diethyl ether, and chloroform.

It dissolves in ethanol.

[6] The compound decomposes when heated in vacuum: It hydrolyzes in hot water:[7] Reacts with chlorine and bromine: