Contents

Thorium(IV) bromide

Thorium(IV) bromide

Identifiers
CAS Number	13453-49-1 anhydrous Y 20333-47-5 octahydrate Y
3D model (JSmol)	Interactive image
ChemSpider	75321
ECHA InfoCard	100.033.285
EC Number	236-628-9
PubChem CID	83483
CompTox Dashboard (EPA)	DTXSID1065473
InChI InChI=1S/4BrH.Th/h4*1H;/q;;;;+4/p-4 Key: OMDXFCRSKHYDTM-UHFFFAOYSA-J
SMILES Br[Th](Br)(Br)Br
Properties
Chemical formula	ThBr4
Molar mass	551.65
Appearance	white solid
Density	5.72 g·cm−3 (α) 5.76 g·cm−3 (β)
Melting point	678±5 °C[1]
Solubility in water	soluble
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Chemical compound

Thorium(IV) bromide is an inorganic compound, with the chemical formula of ThBr₄.

Thorium(IV) bromide can be obtained by reacting thorium dioxide, bromine and carbon at 800~900 °C. This method produces a mixture of alpha and beta forms of thorium bromide. The pure α-form product is obtained by heating the mixture at 330~375 °C for a long time. The pure β form is obtained by heating the product to 470 °C and then rapidly cooling it in ice water.^[2]

ThO₂ + 2 C + 2 Br₂ ⟶ ThBr₄ + 2 CO

Thorium(IV) bromide can also be produced by the reaction of thorium and bromine. Thorium hydroxide reacts with hydrobromic acid to crystallize hydrates from the solution.^[3]

Thorium(IV) bromide exists in low-temperature α-type and high-temperature β-type. They are both white deliquescent solids and are easily soluble in water, ethanol and ethyl acetate. It reacts with fluorine gas under standard conditions and with chlorineoroxygen when heated. The beta form of thorium bromide is metastable at room temperature and converts to the alpha form over 10 to 12 weeks, with the conversion from alpha to beta occurring at around 420 °C. The α-type thorium(IV) bromide is an orthorhombic crystal, while the β-type thorium(IV) bromide is a tetragonal crystal with space group I4₁/amd. Some of its hydrates are known, and these hydrates form thorium oxybromide on heating.^[3]

• Mikheev, N. B.; Kamenskaya, A. N.; Kulyukhin, S. A.; Rumer, I. A.; Novichenko, V. L. (2001). "Sorption of CH3131I from the Gas Phase on Modified Metal-Substituted Zeolites Containing Copper and Silver Ions". Radiochemistry. 43 (3): 293–296. doi:10.1023/a:1012868726987. ISSN 1066-3622. S2CID 92635246.