Protactinium(V) iodide explained

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

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.^[1]

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. It reacts with the monocarbide at 600 °C to give tetraiodide.^[2]

Aristid von Grosse was able to produce pure metallic protactinium with the decomposition of protactinium(V) iodide.^{[3] [4]}

When heated at 300 °C for a long time, it decomposes and iodine is released:^[5]

PaI₅ → PaI₃ + I₂

Notes and References

1. Journal of the Chemical Society A: Inorganic, Physical, Theoretical. en. 0022-4944. 1967. 1698–1702. 10.1039/j19670001698. Protactinium(V) iodides. 2021-09-25. D. Brown, J. F. Easey, P. J. Jones.
2. Brown, David; De Paoli, Giovanni; Whittaker, Brian. Conversion of protactinium monocarbide to the penta- and tetrahalides. Journal of the Chemical Society, Dalton Transactions: Inorganic Chemistry (1972-1999), 1976. 14: 1336-1338.
3. Aristid . von Grosse . . 1934 . Element 91 . 80 . 2084 . 512–516 . 10.1126/science.80.2084.512 . 17734249. 1934Sci....80..512G .
4. 10.1002/cber.19350680218 . Zur Herstellung von Protactinium . For the production of protactinium . German . 1935 . von Grosse . Aristid . . 68 . 307–309 . 2.
5. Inorganic and Nuclear Chemistry Letters. 3. 12. en. December 1967. 589–595. 10.1016/0020-1650(67)80033-3. Evidence for the existence of protactinium(III) in solid state. 2021-09-25. V. Scherer, F. Weigel, M. Van Ghemen. 2018-06-17. https://web.archive.org/web/20180617160211/https://linkinghub.elsevier.com/retrieve/pii/0020165067800333.