Diselenium dibromide

Structural formula
No drawing available
General
Surname	Diselenium dibromide
other names	Selenium (I) bromide Selenium monobromide
Molecular formula	Se 2 Br 2
Brief description	red liquid
External identifiers / databases
CAS number 7789-52-8 EC number 232-173-5 ECHA InfoCard 100.029.248 PubChem 82243 ChemSpider 74221 Wikidata Q27264097
properties
Molar mass	317.73 g mol −1
Physical state	liquid
density	3.6 g cm −3
Melting point	−49 ° C
boiling point	225 ° C (decomposition)
solubility	reacts with water soluble in chloroform and carbon sulfide
safety instructions
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary danger H and P phrases H: 331-301-373-410 P: ?
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Diselendibromide is an inorganic chemical compound of selenium from the group of bromides .

Extraction and presentation

Disele dibromide can be obtained by reacting selenium with bromine .

${\displaystyle {\ce {2Se + Br2 ->Se2Br2}}}$

It is also possible to display it by reacting selenium with selenium dioxide and hydrogen bromide .

${\displaystyle {\ce {3 Se + SeO2 + 4 HBr -> 2 Se2Br2 + 2 H2O}}}$

properties

Diselenium dibromide is a dark red, hygroscopic , almost black, oily liquid with an unpleasant odor. In the air, it rapidly releases bromine with simultaneous selenium separation. When heated, the compound partially disintegrates, in that bromine initially escapes, then some selenium tetrabromide sublimates and between 225 ° C and 230 ° C part of the diselenium dibromide boils without decomposition, while some selenium remains. In water, diselene dibromide sinks to the bottom in oily drops and gradually decomposes into selenium, selenium dioxide and hydrogen bromide.

Diselenium dibromide has a metastable β-form with a monoclinic crystal structure at -80 ° C with the space group P 2 ₁ / c (space group no. 14) which consists of BrSeSeBr molecules. The α-form has the orthorhombic crystal structure with the space group Aea 2 (space group no. 41) .

use

Diselene dibromide can be used to make other chemical compounds such as selenium cyanide .

${\displaystyle {\ce {2 Se2Br2 + 4 AgCN -> 4 AgBr + Se(CN)2 + Se3(CN)2}}}$

Individual evidence

1. ↑ ^{a b c d e} David R. Lide: CRC Handbook of Chemistry and Physics A Ready-reference Book of Chemical and Physical Data . CRC Press, 1995, ISBN 978-0-8493-0595-5 , pp. 81 ( limited preview in Google Book search).
2. ↑ ^{a b} Rüdiger Kniep, Lutz Körte, Dietrich Mootz: Crystal Structures of Compounds A2X2 (A = S, Se; X = Cl, Br) / Crystal Structures of Compounds A2X2 (A = S, Se; X = Cl, Br). In: Zeitschrift für Naturforschung B. 38, 1983, p. 1, doi : 10.1515 / znb-1983-0102 .
3. ↑ Entry on selenium compounds in the GESTIS substance database of the IFA , accessed on February 15, 2020(JavaScript required) .
4. ↑ Entry on selenium compounds in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 15, 2020. Manufacturers or distributors can expand the harmonized classification and labeling .
5. ↑ ^{a b c} Georg Brauer: Handbook of preparative inorganic chemistry . F. Enke, 1975, ISBN 978-3-432-02328-1 , pp. 418 ( limited preview in Google Book search).
6. ↑ Julius Meyer, V. Wurm: About the decomposition of hydrobromic acid and its salts. In: Journal of Inorganic and General Chemistry. 190, 1930, p. 90, doi : 10.1002 / zaac.19301900110 .
7. ↑ Marc Lamoureux, John Milne: The disproportionation of diselenium dichloride, Se2Cl2, and diselenium dibromide, Se2Br2. In: Canadian Journal of Chemistry. 67, 1989, p. 1936, doi : 10.1139 / v89-301 .
8. ↑ The former name of this group of rooms was Aba 2.
9. ↑ Detlef Katryniok, Rüdiger Kniep: Molecular and Crystal Structure of β-SeBr. In: Angewandte Chemie International Edition in English. 19, 1980, p. 645, doi : 10.1002 / anie.198006451 .
10. ↑ Joachim Goerdeler, Peter Müller, Heidi Müller-Dolezal, Renate Stoltz, Hanna Söll: Houben-Weyl Methods of Organic Chemistry Vol. IX, 4th Edition Sulfur, Selenium, Tellurium Compounds . Georg Thieme Verlag, 2014, ISBN 3-13-180544-7 , p. 1086 ( limited preview in Google Book Search).