Nickel(II) fluoride

Nickel(II) fluoride
Names


IUPAC name Nickel(II) fluoride
Identifiers
CAS Number	10028-18-9^Y
3D model (JSmol)	Interactive image
ChemSpider	23210^Y
ECHA InfoCard	100.030.053
EC Number	233-071-3
PubChem CID	24825
RTECS number	QR6825000
UNII	69NBB20493^N
CompTox Dashboard (EPA)	DTXSID5064912
InChI InChI=1S/2FH.Ni/h21H;/q;;+2/p-2^Y Key: DBJLJFTWODWSOF-UHFFFAOYSA-L^Y InChI=1S/2FH.Ni/h21H;/q;;+2/p-2 Key: DBJLJFTWODWSOF-NUQVWONBAA Key: DBJLJFTWODWSOF-UHFFFAOYSA-L
SMILES F[Ni]F
Properties
Chemical formula	NiF₂
Molar mass	96.6902 g/mol
Appearance	Yellowish to green tetragonal crystals
Density	4.72 g/cm³
Melting point	1,474 °C (2,685 °F; 1,747 K)^[1]
Solubility in water	4 g/100 mL
Solubility	insoluble in alcohol, ether
Magnetic susceptibility (χ)	+2410.0·10⁻⁶ cm³/mol
Structure
Crystal structure	Rutile
Coordination geometry	Nickel: Octahedral Oxygen: Trigonal planar
Hazards
Safety data sheet (SDS)	External MSDS
Related compounds
Other anions	Nickel(II) chloride Nickel(II) bromide Nickel(II) iodide
Other cations	Cobalt(II) fluoride Copper(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

Chemical compound

Nickel(II) fluoride is the chemical compound with the formula NiF₂. It is an ionic compound of nickel and fluorine and forms yellowish to green tetragonal crystals. Unlike many fluorides, NiF₂ is stable in air.

Nickel(II) fluoride is also produced when nickel metal is exposed to fluorine. In fact, NiF₂ comprises the passivating surface that forms on nickel alloys (e.g. monel) in the presence of hydrogen fluoride or elemental fluorine. For this reason, nickel and its alloys are suitable materials for storage and transport these fluorine and related fluorinating agents. NiF₂ is also used as a catalyst for the synthesis of chlorine pentafluoride.

Preparation and structure

NiF₂ is prepared by treatment of anhydrous nickel(II) chloride with fluorine at 350 °C:^[2]

NiCl₂ + F₂ → NiF₂ + Cl₂

The corresponding reaction of cobalt(II) chloride results in oxidation of the cobalt, whereas nickel remains in the +2 oxidation state after fluorination because its +3 oxidation state is less stable. Chloride is more easily oxidized than nickel(II). This is a typical halogen displacement reaction, where a halogen plus a less active halide makes the less active halogen and the more active halide.

Like some other metal difluorides, NiF₂ crystallizes in the rutile structure, which features octahedral Ni centers and planar fluorides.^[3] At low temperatures, its magnetic structure is antiferromagnetic.^[4]S

Reactions

A melt of NiF₂ and KF reacts to give successively potassium trifluoronickelate and potassium tetrafluoronickelate:^[5]

NiF₂ + KF → K[NiF₃]

K[NiF₃] + KF → K₂[NiF₄]

The structure of this material is closely related to some superconducting oxide materials.^[6]

Nickel(II) fluoride reacts with strong bases to give nickel(II) hydroxide:

NiF₂ + 2 NaOH → Ni(OH)₂ + 2 NaF

References

^ Planning. Validations stanford.edu ^{[dead link]}
^ Priest, H. F. (1950). "Anhydrous Metal Fluorides". Inorganic Syntheses. Vol. 3. pp. 171–183. doi:10.1002/9780470132340.ch47. ISBN 9780470132340.
^ Stout, J. W.; Reed, Stanley A. (1954). "The Crystal Structure of MnF₂, FeF₂, CoF₂, NiF₂ and ZnF₂". J. Am. Chem. Soc. 76 (21): 5279–5281. doi:10.1021/ja01650a005.
^ Strempfer, J; Ruett, U; Bayrakci, S.P.; Brueckel, Th.; Jauch, W (2004). "Magnetic properties of transition metal fluorides". Phys. Rev. B. 69: 014417. doi:10.1103/PhysRevB.69.014417.
^ Plevey, R. G.; Rendell, R. W.; Steward, M. P. (1974-01-01). "Fluorination with complex metal fluorides Part III. The fluorination of benzene over potassium hexafluoronickelate(IV)". Journal of Fluorine Chemistry. 3 (3–4): 267–273. Bibcode:1974JFluC...3..267P. doi:10.1016/S0022-1139(00)82626-3. ISSN 0022-1139.
^ Balz, D. (1953). "Über die Struktur des K₂NiF₄". Naturwissenschaften. 40 (8): 241. Bibcode:1953NW.....40..241B. doi:10.1007/BF00591545. S2CID 32692990.