Mercury(I) bromide

Mercury(I) bromide
IUPAC name Mercury(I) bromide
Other names Mercurous bromide
Identifiers
CAS number	15385-58-7
RTECS number	?
Properties
Molecular formula	Hg2Br2
Molar mass	560.99 g/mol
Appearance	white tetragonal crystals
Density	7.307 g/cm³, solid
Melting point	405°C
Boiling point	sublimes at 340-350°C [1]
Solubility in water	3.9 x 10-5 g/100 mL
Structure
Molecular shape	linear
Hazards
EU classification	Very toxic (T+) Dangerous for the environment (N)
R-phrases	R26/27/28, R33, R50/53
S-phrases	S13, S28, S45, S60, S61[2]
Flash point	non-flammable
Related compounds
Other anions	Mercury(I) fluoride Mercury(I) chloride Mercury(I) iodide
Other cations	Zinc bromide Cadmium bromide Mercury(II) bromide
Y bromide (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Mercury(I) bromide or mercurous bromide is the chemical compound composed of mercury and bromine with the formula Hg₂Br₂. It changes color from white to yellow when heated^[1] and fluoresces orange when exposed to ultraviolet light. It has applications in acousto-optical devices.^[3]

A very rare mineral form is called kuzminite, Hg₂(Br,Cl)₂.

Reactions

Mercury(I) bromide is prepared by the oxidation of elemental mercury with elemental bromine or by adding sodium bromide to a solution of mercury(I) nitrate^[1]. It decomposes to mercury(II) bromide and elemental mercury^[when?][3].

Structure

In common with other Hg(I) (mercurous) compounds which contain linear X-Hg-Hg-X units, Hg₂Br₂ contains linear BrHg₂Br units with an Hg-Hg bond length of 249 pm (Hg-Hg in the metal is 300 pm) and an Hg-Br bond length of 271 pm.^[4] The overall coordination of each Hg atom is octahedral as, in addition to the two nearest neighbours, there are four other Br atoms at 332 pm.^[4] The compound is often formulated as Hg₂²⁺ 2Br⁻.^[5]

References

1. ^ ^{a b c} Perry, Dale L.; Phillips, Sidney L. (1995), Handbook of Inorganic Compounds, CRC Press, pp. 255, ISBN 0849386713, http://books.google.com/?id=0fT4wfhF1AsC&pg=PA255&dq=%22Mercury(I)+bromide%22, retrieved 2008-05-30 
2. ^ "483230 Mercury(I) bromide 99.9+ %". Sigma-Aldrich. http://www.sigmaaldrich.com/catalog/search/ProductDetail/ALDRICH/483230. Retrieved 2008-05-30. 
3. ^ ^{a b} Macintyre, Jane Elizabeth; Daniel, F. M.; Stirling, V. M. (1992), Dictionary of Inorganic Compounds, 1, CRC Press, pp. 314, ISBN 0412301202, http://books.google.com/?id=YmBiXJ7qRtAC&pg=PA314&dq=Mercury(I)+bromide, retrieved 2008-05-30 
4. ^ ^{a b} Wells A.F. (1984) Structural Inorganic Chemistry 5th edition Oxford Science Publications ISBN 0-19-855370-6
5. ^ Cotton, F. Albert; Wilkinson, Geoffrey; Murillo, Carlos A.; Bochmann, Manfred (1999), Advanced Inorganic Chemistry (6th ed.), New York: Wiley-Interscience, ISBN 0-471-19957-5