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| Names | |
|---|---|
| IUPAC name silver(II) fluoride | |
| Other names silver difluoride | |
| Identifiers | |
3D model (JSmol) | |
| ChemSpider |
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| ECHA InfoCard | 100.029.124 |
| EC Number |
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| UNII | |
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| Properties | |
| AgF2 | |
| Molar mass | 145.865 g/mol |
| Appearance | white or grey crystalline powder,hygroscopic |
| Density | 4.58 g/cm3 |
| Melting point | 690 °C (1,274 °F; 963 K) |
| Boiling point | 700 °C (1,292 °F; 973 K) (decomposes) |
| Decomposes | |
| Structure | |
| orthorhombic | |
| tetragonally elongated octahedral coordination | |
| linear | |
| Hazards | |
| Occupational safety and health (OHS/OSH): | |
Main hazards | toxic, reacts violently with water, powerful oxidizer |
| GHS labelling: | |
   | |
| Danger | |
| H272,H301,H302,H311,H312,H314,H331,H332 | |
| P210,P220,P221,P260,P261,P264,P270,P271,P280,P301+P310,P301+P312,P301+P330+P331,P302+P352,P303+P361+P353,P304+P312,P304+P340,P305+P351+P338,P310,P311,P312,P321,P322,P330,P361,P363,P370+P378,P403+P233,P405,P501 | |
| NFPA 704 (fire diamond) | |
| Safety data sheet (SDS) | MSDS |
| Related compounds | |
Otheranions | Silver(I,III) oxide |
Othercations | Copper(II) fluoride Palladium(II) fluoride Zinc fluoride Cadmium(II) fluoride Mercury(II) fluoride |
Related compounds | Silver subfluoride Silver(I) fluoride |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Silver(II) fluoride is achemical compound with theformula AgF2. It is a rare example of a silver(II) compound -silver usually exists in its +1oxidation state. It is used as a fluorinating agent.
AgF2 can be synthesized by fluorinating Ag2O with elementalfluorine. Also, at 200 °C (473 K) elemental fluorine will react withAgF orAgCl to produce AgF2.[1][2]
As a strong fluorinating agent, AgF2 should be stored inTeflon or a passivated metal container. It is light sensitive.
AgF2 can be purchased from various suppliers, the demand being less than 100 kg/year. While laboratory experiments find use for AgF2, it is too expensive for large scale industry use. In 1993, AgF2 cost between 1000–1400US dollars per kg.
AgF2 is a white crystalline powder, but it is usually black/brown due to impurities. The F/Ag ratio for most samples is < 2, typically approaching 1.75 due to contamination withAg andoxides andcarbon.[3]
For some time, it was doubted that silver was actually in the +2 oxidation state, rather than some combination of states such as AgI[AgIIIF4], which would be similar tosilver(I,III) oxide.Neutron diffraction studies, however, confirmed its description as silver(II). The AgI[AgIIIF4] was found to be present at high temperatures, but it was unstable with respect to AgF2.[4]
In the gas phase, AgF2 is believed to have D∞hsymmetry. Persingle-crystal X-ray diffraction, the silver atoms aresquare planar-coordinated in the solid state.[5]
Approximately 14kcal/mol (59kJ/mol; 0.61 eV/f.u.) separate theground andfirst excited states. The compound isparamagnetic, but it becomesferromagnetic at temperatures below −110 °C (163 K).
AgF2 is a strongfluorinating andoxidising agent. It is formed as an intermediate in thecatalysis of gaseous reactions with fluorine by silver. With fluoride ions, it forms complex ions such asAgF−
3, the blue-violetAgF2−
4, andAgF4−
6.[6]
It is used in the fluorination and preparation of organic perfluorocompounds.[7] This type of reaction can occur in three different ways (here Z refers to any element or group attached to carbon, X is ahalogen):
Similar transformations can also be effected using other highvalence metallic fluorides such asCoF3, MnF3, CeF4, and PbF4.
AgF
2 is also used in the fluorination ofaromatic compounds, although selective monofluorinations are more difficult:[8]
AgF
2 oxidisesxenon toxenon difluoride inanhydrous HF solutions.[9]
It also oxidisescarbon monoxide tocarbonyl fluoride.
It reacts with water to form oxygen gas:[citation needed]
AgF
2 can be used to selectively fluorinatepyridine at the ortho position under mild conditions.[10]
AgF
2 is a very strong oxidizer that reacts violently with water,[11] reacts with dilute acids to produceozone, oxidizesiodide toiodine,[11][12] and upon contact withacetylene forms the contact explosivesilver acetylide.[13] It is light-sensitive,[11] veryhygroscopic and corrosive. It decomposes violently on contact withhydrogen peroxide, releasing oxygen gas.[13] It also liberatesHF,F
2, and elemental silver.[12]
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