Selenium tetrabromide

Selenium tetrabromide

File:Selenium tetrabromide.jpg
File:Selenium-tetrabromide-tetramer-from-alpha-xtal-3D-bs-17.png
Names
IUPAC name Tetrabromo-λ4-selane
Other names Selenium tetrabromide, selenium(IV) bromide
Identifiers
CAS Number	7789-65-3
3D model (JSmol)	Interactive image
ChemSpider	74224
ECHA InfoCard
EC Number	232-181-9
E number
PubChem CID	82246
UNII	8O54YXR180
CompTox Dashboard (EPA)	{{#property:P3117}}
InChI InChI=1S/Br4Se/c1-5(2,3)4 Key: VTQZBGAODFEJOW-UHFFFAOYSA-N InChI=1/Br4Se/c1-5(2,3)4 Key: VTQZBGAODFEJOW-UHFFFAOYAY
SMILES Br[Se](Br)(Br)Br
Properties
Chemical formula	SeBr4
Molar mass	398.576
Density	4.029 g/cm3
Melting point	75 °C (167 °F; 348 K) (dissolves)
Boiling point	115 °C (239 °F; 388 K) (sublimes)
Structure
Crystal structure	trigonal (α) monoclinic (β)
Space group	P31c, No. 159 (α) C2/c, No.15 (β)
Formula units (Z)	16
Hazards
GHS labelling:
Pictograms	GHS05: CorrosiveGHS06: ToxicGHS08: Health hazardGHS09: Environmental hazard
Signal word	Danger
Hazard statements	H301, H311, H314, H331, H351, H373, H410
Precautionary statements	P201, P202, P260, P261, P264, P270, P271, P273, P280, P281, P301+P310, P301+P330+P331, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P308+P313, P310, P311, P312, P314, P321, P322, P330, P361, P363, P391, P403+P233, P405, P501
Related compounds
Other anions	Selenium tetrafluoride Selenium tetrachloride
Other cations	Tellurium tetrabromide
Related compounds	Selenium dibromide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Selenium tetrabromide is an inorganic compound with a chemical formula SeBr₄.

Preparation

Selenium tetrabromide could be produced by mixing elemental bromine and selenium:

$\mathrm{S}\mathrm{e}\mathrm{+}\mathrm{2}\mathrm{B}{\mathrm{r}}_{\mathrm{2}}\mathrm{\to }\mathrm{S}\mathrm{e}\mathrm{B}{\mathrm{r}}_{\mathrm{4}}$

Properties

Selenium tetrabromide exists in two polymorphs, the trigonal, black α-SeBr₄ and the monoclinic, orange-reddish β-SeBr₄, both of which feature tetrameric cubane-like Se₄Br₁₆ units but differ in how they are arranged. It dissolves in carbon disulfide, chloroform and ethyl bromide, but decomposes in water, so that it produces selenous acid in wet air.

The compound is only stable under a bromine-saturated atmosphere; gas phase measurements of the gas density indicate that the compound decomposes into selenium monobromide and bromine.

$\mathrm{2}\mathrm{S}\mathrm{e}\mathrm{B}{\mathrm{r}}_{\mathrm{4}}\mathrm{\to }\mathrm{S}{\mathrm{e}}_{\mathrm{2}}\mathrm{B}{\mathrm{r}}_{\mathrm{2}}\mathrm{+}\mathrm{3}\mathrm{B}{\mathrm{r}}_{\mathrm{2}}$