Niobium(IV) iodide

Niobium(IV) iodide is an iodide of niobium, with the chemical formula of NbI4.

Preparation
Niobium(IV) iodide can be obtained by the decomposition of niobium(V) iodide under a vacuum at 206-270 °C.

Properties
Niobium(IV) iodide is a grey solid that reacts with water.

Niobium(IV) iodide is an orthorhombic crystal with space group Cmc21 (No. 36). Its crystal is formed by NbI6 octahedra connected by edges and also contains Nb-Nb bonds. At 348 to 417 °C, the crystal structure of niobium(IV) iodide changes. Niobium(IV) iodide turns into a metal under extremely high pressure.