Protactinium(IV) bromide

Protactinium(IV) bromide is an inorganic compound. It is an actinide halide, composed of protactinium and bromine. It is radioactive, and has the chemical formula of PaBr₄. It may be due to the brown color of bromine that causes the appearance of protactinium(IV) bromide to be brown crystals. Its crystal structure is tetragonal.^[1][2] Protactinium(IV) bromide is sublimed in a vacuum at 400 °C.^[1] The protactinium(IV) halide closest in structure to protactinium(IV) bromide is protactinium(IV) chloride.

Protactinium(IV) bromide

Names
IUPAC name Protactinium(IV) tetrabromide
Identifiers
CAS Number	13867-42-0 Y
3D model (JSmol)	Interactive image
InChI InChI=1S/4BrH.Pa/h4*1H;/q;;;;+4/p-4 Key: HWPJRUOTLXLOJI-UHFFFAOYSA-J
SMILES [Pa](Br)(Br)(Br)Br
Properties
Chemical formula	PaBr4
Molar mass	550.652
Appearance	red crystals
Structure
Crystal structure	tetragonal crystal system[1][2]，tI20
Space group	I41/amd , No. 141
Related compounds
Other anions	Protactinium(IV) fluoride Protactinium(IV) chloride Protactinium(IV) iodide
Other cations	Uranium(IV) bromide Thorium(IV) bromide Praseodymium(III) bromide
Related compounds	Protactinium(V) bromide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Preparation

Protactinium(IV) bromide can be prepared by reacting protactinium(V) bromide with hydrogen gas or aluminium:^[3]

${\displaystyle {\mathsf {3PaBr_{5}+Al\ {\xrightarrow {400-450^{o}C}}\ 3PaBr_{4}+AlBr_{3}}}}$

${\displaystyle {\mathsf {2PaBr_{5}+H_{2}\ {\xrightarrow {800^{o}C}}\ 2PaBr_{4}+2HBr}}}$

Properties

Protactinium(IV) bromide reacts with antimony trioxide to form protactinium bromate:^[4]

${\displaystyle {\mathsf {3PaBr_{4}+Sb_{2}O_{3}\ {\xrightarrow {150-200^{o}C}}\ 3PaOBr_{2}+2SbBr_{3}}}}$

See also

• Protactinium(V) bromide