Mercury(I) fluoride

Mercury(I) fluoride
IUPAC name Mercury(I) fluoride
Other names Mercurous fluoride
Identifiers
CAS number	13967-25-4
Properties
Molecular formula	Hg2F2
Molar mass	439.177 g/mol
Appearance	yellow cubic crystals
Density	8.73 g/cm³, solid
Melting point	sublimes at 240°C
Boiling point	decomposes at 570°C [1]
Solubility in water	decomposes
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) chloride Mercury(I) bromide Mercury(I) iodide
Other cations	Zinc fluoride Cadmium fluoride Mercury(II) fluoride
Y fluoride (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) fluoride or mercurous fluoride is the chemical compound composed of mercury and fluorine with the formula Hg₂F₂. It consists of small yellow cubic crystals which turn black when exposed to light^[1].

Reactions

Mercury(I) fluoride is prepared by the reaction of mercury(I) carbonate with hydrofluoric acid. When added to water, it hydrolyzes to elemental liquid mercury, mercury(II) oxide, and hydrofluoric acid^[1]. It can be used in the Swarts reaction to convert alkyl halides into alkyl fluorides ^[3]:

2 R-X + Hg₂F₂ → 2 R-F + Hg₂X₂

where X = Cl, Br, I

Structure

In common with other Hg(I) (mercurous) compounds which contain linear X-Hg-Hg-X units, Hg₂F₂ contains linear FHg₂F units with an Hg-Hg bond length of 251 pm (Hg-Hg in the metal is 300 pm) and an Hg-F bond length of 214 pm.^[4] The overall coordination of each Hg atom is octahedral as it has in addition to the two nearest neighbours there are four other F atoms at 272 pm. ^[4]The compound is often formulated as Hg₂²⁺ 2F⁻.^[5]

References

1. ^ ^{a b c} Perry, Dale L.; Phillips, Sidney L. (1995), Handbook of Inorganic Compounds, CRC Press, pp. 256, ISBN 0849386713, http://books.google.com/?id=0fT4wfhF1AsC&pg=PA256&dq=%22Mercury(I)+fluoride%22, retrieved 2008-06-17 
2. ^ 339318 Mercury(I) fluoride technical grade, Sigma-Aldrich, http://www.sigmaaldrich.com/catalog/search/ProductDetail/ALDRICH/339318, retrieved 2008-06-17 
3. ^ Beyer, Hans; Walter, Wolfgang; Lloyd, Douglas (1997), Organic Chemistry, Horwood Publishing, pp. 136, ISBN 1898563373, http://books.google.com/?id=RXX2RaCplmAC&pg=PA136&dq=%22Mercury(I)+fluoride%22, retrieved 2008-06-17 
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