Protactinium(V) iodide is an inorganic compound, with the

chemical formula In chemistry, a chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbol ...

of PaI₅. It can be prepared by the reaction of metals

protactinium Protactinium (formerly protoactinium) is a chemical element with the symbol Pa and atomic number 91. It is a dense, silvery-gray actinide metal which readily reacts with oxygen, water vapor and inorganic acids. It forms various chemical compounds ...

and iodine, or by reacting

protactinium(V) chloride Protactinium(V) chloride is the chemical compound composed of protactinium and chlorine with the formula PaCl5. It forms yellow monoclinic crystals and has a unique structure composed of chains of 7 coordinate, pentagonal bipyramidal, protactiniu ...

protactinium(V) bromide Protactinium(V) bromide is an inorganic compound. It is a halide of protactinium, consisting of protactinium and bromine. It is radioactive and has a chemical formula of PaBr5, which is a red crystal of the monoclinic crystal system. Preparatio ...

or protactinium(V) oxide with silicon tetraiodide. 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.

Aristid von Grosse Aristid von Grosse (January 1905 – July 21, 1985) was a German nuclear chemist. During his work with Otto Hahn, he got access to waste material from radium production, and with this starting material he was able in 1927 to isolate protact ...

was able to produce pure metallic protactinium with the decomposition of protactinium(V) iodide. When heated at 300 °C for a long time, it decomposes and iodine is released: : PaI₅ → PaI₃ + I₂

References

{{Iodides Protactinium compounds Iodides