Zinc fluoride

Zinc fluoride is an inorganic chemical compound with the chemical formula ZnF₂. It is encountered as the anhydrous form and also as the tetrahydrate, ZnF₂·4H₂O (rhombohedral crystal structure).^[2] It has a high melting point and has the rutile structure containing 6 coordinate zinc, which suggests appreciable ionic character in its chemical bonding.^[3] Unlike the other zinc halides, ZnCl₂, ZnBr₂ and ZnI₂, it is not very soluble in water.^[3]

Zinc fluoride

Zinc fluoride
Names
IUPAC name Zinc(II) fluoride
Other names Zinc difluoride
Identifiers
CAS Number	7783-49-5 Y 13986-18-0 (tetrahydrate) Y
3D model (JSmol)	Interactive image
ChemSpider	22957 Y
ECHA InfoCard	100.029.092
EC Number	232-001-9
PubChem CID	24551
RTECS number	ZH3200000
UNII	L9V334775I Y SQ7815WXFB (tetrahydrate) Y
UN number	3077
CompTox Dashboard (EPA)	DTXSID20894882
InChI InChI=1S/2FH.Zn/h2*1H;/q;;+2/p-2 Y Key: BHHYHSUAOQUXJK-UHFFFAOYSA-L Y
SMILES F[Zn]F
Properties
Chemical formula	ZnF2
Molar mass	103.406 g/mol (anhydrous) 175.45 g/mol (tetrahydrate)
Appearance	white needles hygroscopic
Density	4.95 g/cm3 (anhydrous) 2.30 g/cm3 (tetrahydrate)
Melting point	872 °C (1,602 °F; 1,145 K) (anhydrous) 100 °C, decomposes (tetrahydrate)
Boiling point	1,500 °C (2,730 °F; 1,770 K) (anhydrous)
Solubility in water	.000052 g/(100 mL) (anhydrous) 1.52 g/(100 mL), 20 °C (tetrahydrate)
Solubility	sparingly soluble in HCl, HNO3, ammonia
Magnetic susceptibility (χ)	−38.2·10−6 cm3/mol
Structure
Crystal structure	tetragonal (anhydrous), tP6
Space group	P42/mnm, No. 136
Hazards
GHS labelling:[1]
Pictograms
Signal word	Danger
Hazard statements	H301, H315, H318, H335
Precautionary statements	P261, P264, P270, P271, P280, P301+P310, P302+P352, P304+P340, P305+P351+P338, P310, P312, P330, P332+P313, P337+P313, P362, P403+P233, P405, P501
NFPA 704 (fire diamond)	3 0 0
Related compounds
Other anions	Zinc(II) bromide Zinc(II) chloride Zinc(II) iodide
Other cations	Cadmium(II) fluoride Mercury(II) fluoride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Like some other metal difluorides, ZnF₂ crystallizes in the rutile structure, which features octahedral Zn cations and trigonal planar fluorides.^[4]

Preparation and reactions

Zinc fluoride can be synthesized several ways.

• The reaction of zinc metal with fluorine gas.^[3]
• Reaction of hydrofluoric acid with zinc, to yield hydrogen gas (H₂) and zinc fluoride (ZnF₂).^[3]

Zinc fluoride can be hydrolysed by hot water to form the zinc hydroxide fluoride, Zn(OH)F.^[5]

The salt is believed to form both a tetrahydrate and a dihydrate.^[6]