Protactinium(V) bromide

Protactinium(V) bromide
Names
	IUPAC name Protactinium(V) bromide
Identifiers
CAS Number	15608-38-5 ;
3D model (JSmol)	Interactive image;
	SMILES (Br)(Br)(Br)(Br)Br;
Properties
Chemical formula	PaBr5
Molar mass	630.556 g mol−1
Appearance	red solid
Density	4.98 g/cm3
Structure
Crystal structure	monoclinic
Space group	P21/c , No. 14
Related compounds
Other anions	Protactinium(V) fluoride; Protactinium(V) chloride; Protactinium(V) iodide
Other cations	Praseodymium(III) bromide; Thorium(IV) bromide; Uranium(IV) bromide
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa). Infobox references

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.^[2]^[1]

Preparation

Protactinium(V) bromide can be obtained by reacting protactinium(V) chloride with boron tribromide at 500 to 550 °C.^[3]

3PaCl₅ + 5BBr₃ → 3PaBr₅ + 5BCl₃

It can also be obtained by reacting protactinium(V) oxide with aluminum bromide at 400 °C.^[4]

Physical properties

Protactinium(V) bromide is an orange-red, crystalline, extremely moisture-sensitive solid that reacts violently with water and ammonia, but is persistent in absolutely dry air. It is insoluble in isopentane, dichloromethane and benzene, and in anhydrous acetonitrile is dissolves to form PaBr₅•4CH₃CN. It comes in several modifications. Below 400 °C as an α-modification and above 400 °C as a β-modification. The α-form has a monoclinic crystal structure of the space group P2₁/c (No. 14) and lattice parameters a = 1296 pm, b = 1282 pm, c = 992 pm, β = 108° and the β-form also has monoclinic crystal structure with space group P2₁/n (No. 14, position 2) and lattice parameters a = 838.5 pm, b = 1120.5 pm, c = 895.0 pm, β = 91.1°.^[3] The β form exists as a dimer. At 400 °C in a vacuum, protactinium(V) bromide sublimes.^[5] A γ-form, which has a β-uranium(V) chloride-type crystal structure, has also been detected.^[6]

References

^ ^a ^b Brown, D.; Petcher, T. J.; Smith, A. J. (1968). "Crystal Structures of some Protactinium Bromides". Nature. 217 (5130): 737. Bibcode:1968Natur.217..737B. doi:10.1038/217737a0. S2CID 4264482.
^ ^a ^b Brown, D.; Petcher, T. J.; Smith, A. J. (1969). "The crystal structure of β-protactinium pentabromide". Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry. 25 (2): 178. doi:10.1107/S0567740869007357.
^ ^a ^b Georg Brauer (Hrsg.), unter Mitarbeit von Marianne Baudler u. a.: Handbuch der Präparativen Anorganischen Chemie. 3., umgearbeitete Auflage. Band I, Ferdinand Enke, Stuttgart 1975, ISBN 3-432-02328-6, S. 1177.
^ Advances in Inorganic Chemistry and Radiochemistry (in German), Academic Press, 1970, p. 31
^ D. Brown, T. J. Petcher, A. J. Smith: The crystal structure of β-protactinium pentabromide. In: Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry. 25, S. 178–182, doi:10.1107/S0567740869007357.
^ D. Brown: The polymorphism of protactinium pentabromide. In: Inorganic and Nuclear Chemistry Letters. 15, 1979, S. 219–223, doi:10.1016/0020-1650(79)80132-4.

Zdroj:https://en.wikipedia.org?pojem=Protactinium(V)_bromide
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[pabr5b-1] Brown, D.; Petcher, T. J.; Smith, A. J. (1968). "Crystal Structures of some Protactinium Bromides". Nature. 217 (5130): 737. Bibcode:1968Natur.217..737B. doi:10.1038/217737a0. S2CID 4264482.

[pabr5-2] Brown, D.; Petcher, T. J.; Smith, A. J. (1969). "The crystal structure of β-protactinium pentabromide". Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry. 25 (2): 178. doi:10.1107/S0567740869007357.

[brauer-3] Georg Brauer (Hrsg.), unter Mitarbeit von Marianne Baudler u. a.: Handbuch der Präparativen Anorganischen Chemie. 3., umgearbeitete Auflage. Band I, Ferdinand Enke, Stuttgart 1975, ISBN 3-432-02328-6, S. 1177.

[4] Advances in Inorganic Chemistry and Radiochemistry (in German), Academic Press, 1970, p. 31

[DOI10.1107/S0567740869007357-5] D. Brown, T. J. Petcher, A. J. Smith: The crystal structure of β-protactinium pentabromide. In: Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry. 25, S. 178–182, doi:10.1107/S0567740869007357.

[DOI10.1016/0020-1650(79)80132-4-6] D. Brown: The polymorphism of protactinium pentabromide. In: Inorganic and Nuclear Chemistry Letters. 15, 1979, S. 219–223, doi:10.1016/0020-1650(79)80132-4.

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v t e Protactinium compounds
Pa(II)	PaO
Pa(III)	PaH₃ PaN
Pa(IV)	PaO₂ PaCl₄ PaBr₄ PaF₄ PaI₄ PaOCl₂ PaC Pa(C₈H₈)₂
Pa(V)	Pa₂O₅ PaF₅ PaCl₅ PaBr₅ PaI₅ PaO₂F PaO₂Cl PaO₂I PaO(NO₃)₃