Protactinium tetraiodide

Protactinium tetraiodide is a binary inorganic compound of protactinium metal and iodine with the chemical formula PaI₄.^[1][2]

Protactinium tetraiodide

Identifiers
CAS Number	15513-96-9 Y
3D model (JSmol)	Interactive image
InChI InChI=1S/4HI.Pa/h4*1H;/q;;;;+4/p-4 Key: KIEAWOXJKSIKSB-UHFFFAOYSA-J
SMILES [Pa+4].[I-].[I-].[I-].[I-]
Properties
Chemical formula	I4Pa
Molar mass	738.65376 g·mol−1
Appearance	black crystals
Related compounds
Related compounds	uranium tetraiodide, thorium tetraiodide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Synthesis

Protactinium tetraiodide can be prepared by reducing the pentaiodide with aluminum at about 400 °C:^[3]

3PaI₅ + Al → 3PaI₄ + AlI₃

Also, a reaction of hydrogen reduction of protactinium(V) iodide at 400 °C:^[4]

2PaI₅ + H₂ → 2PaI₄ + 2HI

Physical properties

The compound forms black or dark green crystals.^[4] The structure is not known.^[5]

Chemical properties

The compound is oxidized by antimony trioxide when heated in a vacuum:^[6]

3PaI₄ + Sb₂O₃ → 3PaOI₂ + 2SbI₃

The compound also reacts with quartz when heated:^{[dubious – discuss]}

2PaI₄ + SiO₂ → 2PaOI₂ + SiI₄