protactinium(V) fluoride
{{Chembox
|ImageFile=Beta-UF5.png
|Section1={{Chembox Identifiers
| CASNo=15192-29-7
| CASNo_Ref = {{cascite|correct|CAS}}
| SMILES=F[Pa](F)(F)(F)F
| PubChem = 101946429
| PubChem_Comment = (charge error)
| StdInChI=1S/5FH.Pa/h5*1H;/q;;;;;+5/p-5
| StdInChIKey = LULSFBDYSXVRIJ-UHFFFAOYSA-I
}}
|Section2={{Chembox Properties
|F=5|Pa=1
| Appearance= white solid{{cite book|title=Handbuch der Präparativen Anorganischen Chemie.|isbn=3432023286|page=1170 |last1=Brauer |first1=Georg |date=1975 |publisher=F. Enke }}
|Density=
| MeltingPt=
| BoilingPt=
| Solubility= Soluble in water and hydrofluoric acid
}}
|Section8={{Chembox Related
|OtherAnions=protactinium(V) chloride
protactinium(V) bromide
protactinium(V) iodide
|OtherCations=uranium(V) fluoride
| OtherCompounds=protactinium(IV) fluoride
}}
}}
Protactinium(V) fluoride is a fluoride of protactinium with the chemical formula PaF5.
Preparation
Protactinium(V) fluoride can be obtained by reacting protactinium(V) oxide with bromine trifluoride or bromine pentafluoride at 600 °C:
:3 Pa2O5 + 10 BrF3 (6 BrF5) → 6 PaF5 + 5 Br2 (3 Br2 ) + 7.5 O2
It can also be obtained by reacting protactinium(V) chloride or protactinium(IV) fluoride with fluorine gas at 700 °C:
:{{chem2 | 2 PaF4 + F2 -> 2 PaF5}}
The hydrate form of protactinium(V) fluoride can be formed by the reaction of protactinium(V) oxide and hydrofluoric acid in an aqueous solution:
:{{chem2 | Pa2 O5 + 10 HF -> 2 PaF5 . 2 H2O + 6 H2O}}
It can also be decomposed from fluorine-containing protactinium complexes.{{cite book |author=G. Meyer |author2=Lester R. Morss |title=Synthesis of Lanthanide and Actinide Compounds |publisher=Springer |page=77 |date=1991 |isbn=9780792310181 |language=de |url=https://books.google.com/books?id=bnS5elHL2w8C&pg=PA77}}
Properties
Protactinium(V) fluoride is a white, volatile, extremely hygroscopic solid that is partially soluble in water and soluble in hydrofluoric acid. It has a tetragonal crystal structure of the β-uranium pentafluoride type with the space group I42d (space group no. 122) with the lattice parameters a = 1153 pm, c = 510 pm. Quartz and Pyrex are attacked by the compound at higher temperatures. As a dihydrate, it is a colourless, hygroscopic, crystalline solid that is waxy in nature. It is soluble in water and hydrofluoric acid. It reacts with phosphorus trifluoride to form protactinium(IV) fluoride.{{cite book |editor=Lester R. Morss |editor2=Norman M. Edelstein |editor3=J. Fuger |title=The Chemistry of the Actinide and Transactinide Elements |publisher=Springer |volume=1 |page=198 |isbn=978-94-0070211-0 |date=2010 |language=de}} The dihydrate cannot be converted into the anhydrous form in air, hydrogen fluoride or fluorine at low temperatures. Instead, diprotactinium(V) oxide octafluoride (Pa2OF8) is formed. At higher temperatures around 325 °C, a mixture of the diprotactinium(V) oxide octafluoride and protactinium(V) fluoride is formed.
References
{{reflist}}
{{Fluorides}}
{{Protactinium compounds}}
{{Actinide halides}}