Mercury(I) fluoride

Mercury(I) fluoride
Names
	IUPAC name Dimercury difluoride
	Other names Mercury(I) fluoride; Mercurous fluoride
Identifiers
CAS Number	13967-25-4 ;
3D model (JSmol)	Interactive image;
ChemSpider	21160213;
ECHA InfoCard	100.034.302
EC Number	237-747-9;
PubChem CID	4084556;
UNII	5Q0756885Y ;
CompTox Dashboard (EPA)	DTXSID6064820 ;
	InChI InChI=1S/2FH.2Hg/h21H;;/q;;2+1/p-2 Key: FQZUXVBMUHSNRN-UHFFFAOYSA-L;
	SMILES F[Hg][Hg]F;
Properties
Chemical formula	Hg2F2
Molar mass	439.177 g/mol
Appearance	yellow cubic crystals
Density	8.73 g/cm3, solid
Solubility in water	decomposes
Solubility product (Ksp)	3.1×10−6
Magnetic susceptibility (χ)	−26.5·10−6 cm3/mol
Hazards
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H300, H310, H330, H373, H410
NFPA 704 (fire diamond)	4 0 0
Flash point	non-flammable
Related compounds
Other anions	Mercury(I) chloride; Mercury(I) bromide; Mercury(I) iodide
Other cations	Zinc fluoride; Cadmium fluoride
Related compounds	Mercury(II) fluoride
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) 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]

Synthesis

Mercury(I) fluoride is prepared by the reaction of mercury(I) carbonate with hydrofluoric acid:

Hg₂CO₃ + 2 HF → Hg₂F₂ + CO₂ + H₂O

Reactions

When added to water, mercury(I) fluoride hydrolyzes to elemental liquid mercury, mercury(II) oxide, and hydrofluoric acid:^[1]

Hg₂F₂ + H₂O → Hg + HgO + 2 HF

It can be used in the Swarts reaction to convert alkyl halides into alkyl fluorides:^[4]

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.^[5] The overall coordination of each Hg atom is a distorted octahedron; in addition to the bonded F and other Hg of the molecule, there are four other F atoms at 272 pm.^[5] The compound is often formulated as Hg²⁺
₂[F⁻]₂.^[6]

References

^ ^a ^b ^c Perry, Dale L.; Phillips, Sidney L. (1995), Handbook of Inorganic Compounds, CRC Press, p. 256, ISBN 0-8493-8671-3, retrieved 2008-06-17
^ John Rumble (June 18, 2018). CRC Handbook of Chemistry and Physics (99 ed.). CRC Press. pp. 5–189. ISBN 978-1138561632.
^ 339318 Mercury(I) fluoride technical grade, Sigma-Aldrich, retrieved 2008-06-17
^ Beyer, Hans; Walter, Wolfgang; Lloyd, Douglas (1997), Organic Chemistry, Horwood Publishing, p. 136, ISBN 1-898563-37-3, retrieved 2008-06-17
^ ^a ^b Wells A.F. (1984) Structural Inorganic Chemistry 5th edition Oxford Science Publications ISBN 0-19-855370-6
^ 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

[hand-1] Perry, Dale L.; Phillips, Sidney L. (1995), Handbook of Inorganic Compounds, CRC Press, p. 256, ISBN 0-8493-8671-3, retrieved 2008-06-17

[crc-2] John Rumble (June 18, 2018). CRC Handbook of Chemistry and Physics (99 ed.). CRC Press. pp. 5–189. ISBN 978-1138561632.

[sa-3] 339318 Mercury(I) fluoride technical grade, Sigma-Aldrich, retrieved 2008-06-17

[org-4] Beyer, Hans; Walter, Wolfgang; Lloyd, Douglas (1997), Organic Chemistry, Horwood Publishing, p. 136, ISBN 1-898563-37-3, retrieved 2008-06-17

[Wells-5] Wells A.F. (1984) Structural Inorganic Chemistry 5th edition Oxford Science Publications ISBN 0-19-855370-6

[Cotton-6] 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

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