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Mercury(I) bromide

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 a salmon color when exposed to ultraviolet light. It has applications in acousto-optical devices.[3]

Mercury(I) bromide
Mercury(I) bromide
IUPAC name
Mercury(I) bromide
Other names
Mercurous bromide
ECHA InfoCard 100.150.337
Molar mass 560.99 g/mol
Appearance white to yellow tetragonal crystals
Odor odorless
Density 7.307 g/cm3, solid
Melting point 405 °C (761 °F; 678 K)
Boiling point ~ 390 °C (734 °F; 663 K) sublimes[1]
3.9 x 10−5 g/100 mL
Solubility insoluble in ether, acetone, alcohol
−28.6·10−6 cm3/mol
Very toxic (T+)
Dangerous for
the environment (N)
R-phrases (outdated) R26/27/28, R33, R50/53
S-phrases (outdated) S13, S28, S45, S60, S61[2]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
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

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


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]


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] although it is actually a molecular compound.


  1. ^ a b c Perry, Dale L.; Phillips, Sidney L. (1995), Handbook of Inorganic Compounds, CRC Press, p. 255, ISBN 0-8493-8671-3, retrieved 2008-05-30
  2. ^ "483230 Mercury(I) bromide 99.9+ %". Sigma-Aldrich. Retrieved 2008-05-30.
  3. ^ a b Macintyre, Jane Elizabeth; Daniel, F. M.; Stirling, V. M. (1992), Dictionary of Inorganic Compounds, 1, CRC Press, p. 314, ISBN 0-412-30120-2, 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