Protactinium(V) iodide

Protactinium(V) iodide is an inorganic compound, with the chemical formula of PaI₅.

Protactinium(V) iodide

Names
Other names Protactinium pentaiodide
Identifiers
CAS Number	17497-66-4 Y
3D model (JSmol)	Interactive image
InChI InChI=1S/5FH.Pa/h5*1H;/q;;;;;+5/p-5 Key: LULSFBDYSXVRIJ-UHFFFAOYSA-I
SMILES F[Pa](F)(F)(F)F
Properties
Chemical formula	I5Pa
Molar mass	865.55823 g·mol−1
Appearance	black needle crystals[1]
Related compounds
Other anions	Protactinium(V) fluoride Protactinium(V) chloride Protactinium(V) bromide
Other cations	Praseodymium(III) iodide Thorium(IV) iodide Uranium(IV) iodide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Preparation

It can be prepared by the reaction of metals protactinium and iodine, or by reacting protactinium(V) chloride, protactinium(V) bromide or protactinium(V) oxide with silicon tetraiodide.^[2]

Properties

It reacts with antimony trioxide in a vacuum at 150 °C to give the iodide oxides PaOI₃ and PaO₂I; it reacts with protactinium(V) bromide at 350 °C to obtain mixed halides PaBr₃I₂.^[2] It reacts with the monocarbide at 600 °C to give protactinium tetraiodide.^[3]

Aristid von Grosse was able to produce pure metallic protactinium with the decomposition of protactinium(V) iodide.^[4][5]

When heated at 300 °C for a long time, it decomposes and iodine is released:^[1]

PaI₅ → PaI₃ + I₂