Silver(II) fluoride is a

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

with the

formula In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informal use of the term ''formula'' in science refers to the general construct of a relationship betwe ...

AgF₂. It is a rare example of a silver(II) compound.

Silver Silver is a chemical element with the symbol Ag (from the Latin ', derived from the Proto-Indo-European ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, white, lustrous transition metal, it exhibits the highest electrical ...

usually exists in its +1

oxidation state In chemistry, the oxidation state, or oxidation number, is the hypothetical charge of an atom if all of its bonds to different atoms were fully ionic. It describes the degree of oxidation (loss of electrons) of an atom in a chemical compound. C ...

. It is used as a fluorinating agent.

Preparation

AgF₂ can be synthesized by fluorinating Ag₂O with elemental

fluorine Fluorine is a chemical element with the symbol F and atomic number 9. It is the lightest halogen and exists at standard conditions as a highly toxic, pale yellow diatomic gas. As the most electronegative reactive element, it is extremely reactiv ...

. Also, at 200 °C (473 K) elemental fluorine will react with AgF or AgCl to produce AgF₂. As a strong fluorinating agent, AgF₂ should be stored in

Teflon Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene that has numerous applications. It is one of the best-known and widely applied PFAS. The commonly known brand name of PTFE-based composition is Teflon by Chemo ...

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 1000-1400

US dollar The United States dollar ( symbol: $; code: USD; also abbreviated US$ or U.S. Dollar, to distinguish it from other dollar-denominated currencies; referred to as the dollar, U.S. dollar, American dollar, or colloquially buck) is the officia ...

s per kg.

Composition and structure

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 with Ag and

oxides An oxide () is a chemical compound that contains at least one oxygen atom and one other element in its chemical formula. "Oxide" itself is the dianion of oxygen, an O2– (molecular) ion. with oxygen in the oxidation state of −2. Most of the E ...

and

carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon ma ...

. For some time, it was doubted that silver was actually in the +2 oxidation state, rather than some combination of states such as Ag^I g^IIIF₄ which would be similar to

silver(I,III) oxide Silver(I,III) oxide or tetrasilver tetroxide is the inorganic compound with the formula Ag4O4. It is a component of silver zinc batteries. It can be prepared by the slow addition of a silver(I) salt to a persulfate solution e.g. AgNO3 to a Na2 ...

Neutron diffraction Neutron diffraction or elastic neutron scattering is the application of neutron scattering to the determination of the atomic and/or magnetic structure of a material. A sample to be examined is placed in a beam of thermal or cold neutrons to ob ...

studies, however, confirmed its description as silver(II). The Ag^I g^IIIF₄was found to be present at high temperatures, but it was unstable with respect to AgF₂. In the gas phase, AgF₂ is believed to have D_∞h

symmetry Symmetry (from grc, συμμετρία "agreement in dimensions, due proportion, arrangement") in everyday language refers to a sense of harmonious and beautiful proportion and balance. In mathematics, "symmetry" has a more precise definiti ...

. Approximately 14

kcal The calorie is a unit of energy. For historical reasons, two main definitions of "calorie" are in wide use. The large calorie, food calorie, or kilogram calorie was originally defined as the amount of heat needed to raise the temperature of o ...

/ mol (59 kJ/mol) separate the

ground Ground may refer to: Geology * Land, the surface of the Earth not covered by water * Soil, a mixture of clay, sand and organic matter present on the surface of the Earth Electricity * Ground (electricity), the reference point in an electrical c ...

and first excited states. The compound is

paramagnetic Paramagnetism is a form of magnetism whereby some materials are weakly attracted by an externally applied magnetic field, and form internal, induced magnetic fields in the direction of the applied magnetic field. In contrast with this behavior, ...

, but it becomes

ferromagnetic Ferromagnetism is a property of certain materials (such as iron) which results in a large observed magnetic permeability, and in many cases a large magnetic coercivity allowing the material to form a permanent magnet. Ferromagnetic materials ...

at temperatures below −110 °C (163 K).

Uses

AgF₂ is a strong fluorinating and oxidising agent. It is formed as an intermediate in the

catalysis Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...

of gaseous reactions with fluorine by silver. With fluoride ions, it forms complex ions such as , the blue-violet , and . It is used in the fluorination and preparation of organic perfluorocompounds. This type of reaction can occur in three different ways (here Z refers to any element or group attached to carbon, X is a

halogen The halogens () are a group in the periodic table consisting of five or six chemically related elements: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astatine (At), and tennessine (Ts). In the modern IUPAC nomenclature, this grou ...

): # CZ₃H + 2 AgF₂ → CZ₃F + HF + 2 AgF # CZ₃X + 2AgF₂ → CZ₃F + X₂ + 2 AgF # Z₂C=CZ₂ + 2 AgF₂ → Z₂CFCFZ₂ + 2 AgF Similar transformations can also be effected using other high valence metallic fluorides such as CoF₃, MnF₃, CeF₄, and PbF₄. is also used in the fluorination of

aromatic In chemistry, aromaticity is a chemical property of cyclic ( ring-shaped), ''typically'' planar (flat) molecular structures with pi bonds in resonance (those containing delocalized electrons) that gives increased stability compared to satur ...

compounds, although selective monofluorinations are more difficult: :C₆H₆ + 2 AgF₂ → C₆H₅F + 2 AgF + HF oxidises

xenon Xenon is a chemical element with the symbol Xe and atomic number 54. It is a dense, colorless, odorless noble gas found in Earth's atmosphere in trace amounts. Although generally unreactive, it can undergo a few chemical reactions such as the ...

xenon difluoride Xenon difluoride is a powerful fluorinating agent with the chemical formula , and one of the most stable xenon compounds. Like most covalent inorganic fluorides it is moisture-sensitive. It decomposes on contact with water vapor, but is otherwis ...

anhydrous A substance is anhydrous if it contains no water. Many processes in chemistry can be impeded by the presence of water; therefore, it is important that water-free reagents and techniques are used. In practice, however, it is very difficult to achi ...

HF solutions. :2 AgF₂ + Xe → 2 AgF + XeF₂ It also oxidises

carbon monoxide Carbon monoxide ( chemical formula CO) is a colorless, poisonous, odorless, tasteless, flammable gas that is slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the simpl ...

carbonyl fluoride Carbonyl fluoride is a chemical compound with the formula COF2. It is a carbon oxohalide. This gas, like its analog phosgene, is colourless and highly toxic. The molecule is planar with ''C''2v symmetry, bond lengths of 1.174 Å (C=O) and 1.312 ...

. :2 AgF₂ + CO → 2 AgF + COF₂ It reacts with water to form oxygen gas: :4 AgF₂ + 4 H₂O → 2 Ag₂O + 8 HF + O₂ can be used to selectively fluorinate

pyridine Pyridine is a basic heterocyclic organic compound with the chemical formula . It is structurally related to benzene, with one methine group replaced by a nitrogen atom. It is a highly flammable, weakly alkaline, water-miscible liquid w ...

at the ortho position under mild conditions.

Safety

is a very strong oxidizer that reacts violently with water, reacts with dilute acids to produce

ozone Ozone (), or trioxygen, is an inorganic molecule with the chemical formula . It is a pale blue gas with a distinctively pungent smell. It is an allotrope of oxygen that is much less stable than the diatomic allotrope , breaking down in the l ...

, oxidizes

iodide An iodide ion is the ion I−. Compounds with iodine in formal oxidation state −1 are called iodides. In everyday life, iodide is most commonly encountered as a component of iodized salt, which many governments mandate. Worldwide, iodine de ...

iodine Iodine is a chemical element with the Symbol (chemistry), symbol I and atomic number 53. The heaviest of the stable halogens, it exists as a semi-lustrous, non-metallic solid at standard conditions that melts to form a deep violet liquid at , ...

, and upon contact with

acetylene Acetylene ( systematic name: ethyne) is the chemical compound with the formula and structure . It is a hydrocarbon and the simplest alkyne. This colorless gas is widely used as a fuel and a chemical building block. It is unstable in its pure ...

forms the contact explosive silver acetylide. It is light-sensitive, very

hygroscopic Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption or adsorption from the surrounding environment, which is usually at normal or room temperature. If water molecules become suspended among the substance' ...

and corrosive. It decomposes violently on contact with

hydrogen peroxide Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscous than water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3 ...

, releasing oxygen gas. It also liberates HF, , and elemental silver.

References

External links

National Pollutant Inventory Fluoride and compounds fact sheet
{{DEFAULTSORT:Silver(Ii) Fluoride Fluorides Silver compounds Metal halides Fluorinating agents