The valence electron arrangement of tungsten does not follow hund's rules. Tungsten is one of the transition metal elements in the sixth period (second long period) of the periodic table of elements VIB group. Transition metal elements are obviously different from other elements because of their unfilled valence layer d orbitals based on the eighteen-electron rule.

Tungsten diiodide (WI₂) is an inorganic compound composed of the transition metal element tungsten and the halogen element iodine. It has many chemical properties, which will be described one by one below.

Tungsten diiodide (chemical formula: WI₂) is a kind of inorganic compound formed by the reaction of tungsten and iodine, which has the following chemical properties.

A small amount of tungsten diiodide has low theoretical toxicity and will not harm health.