Silver hexafluorophosphate, sometimes referred to "silver PF-6," is an
inorganic compound
An inorganic compound is typically a chemical compound that lacks carbon–hydrogen bondsthat is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as ''inorganic chemistry''.
Inorgan ...
with the
chemical formula
A chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, such as pare ...
AgPF
6.
Uses and reactions
Silver hexafluorophosphate is a commonly encountered reagent in
inorganic
An inorganic compound is typically a chemical compound that lacks carbon–hydrogen bondsthat is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemistry''.
Inor ...
and
organometallic chemistry
Organometallic chemistry is the study of organometallic compounds, chemical compounds containing at least one chemical bond between a carbon atom of an organic molecule and a metal, including alkali, alkaline earth, and transition metals, and so ...
. It is commonly used to replace
halide
In chemistry, a halide (rarely halogenide) is a binary chemical compound, of which one part is a halogen atom and the other part is an element or radical that is less electronegative (or more electropositive) than the halogen, to make a fl ...
ligands with the
weakly coordinating hexafluorophosphate
Hexafluorophosphate is an fluoroanion, anion with chemical formula of . It is an Octahedral molecular geometry, octahedral species that imparts no color to its salts. is isoelectronic with sulfur hexafluoride, , and the Hexafluorosilicic acid, h ...
anion; abstraction of the halide is driven by the precipitation of the appropriate
silver halide
A silver halide (or silver salt) is one of the chemical compounds that can form between the Chemical element, element silver (Ag) and one of the halogens. In particular, bromine (Br), chlorine (Cl), iodine (I) and fluorine (F) may each combine wit ...
. Illustrative is the preparation of acetonitrile complexes from a metal bromide, a reaction that would typically be conducted in a solution of
acetonitrile
Acetonitrile, often abbreviated MeCN (methyl cyanide), is the chemical compound with the formula and structure . This colourless liquid is the simplest organic nitrile (hydrogen cyanide is a simpler nitrile, but the cyanide anion is not class ...
:
:AgPF
6 + Re(CO)
5Br + CH
3CN → AgBr +
e(CO)5(CH3CN)F
6
Ligands with tightly-bound halide atoms coordinate the silver, but do not themselves decompose:
:AgPF
6 + 2
XeF2 →
g(XeF2)2F
6.
AgPF
6 can act as an oxidant, forming silver metal as a by-product. For example, in solution in dichloromethane,
ferrocene
Ferrocene is an organometallic chemistry, organometallic compound with the formula . The molecule is a Cyclopentadienyl complex, complex consisting of two Cyclopentadienyl anion, cyclopentadienyl rings sandwiching a central iron atom. It is an o ...
is oxidised to
ferrocenium hexafluorophosphate:
:AgPF
6 + Fe(C
5H
5)
2 → Ag +
e(C5H5)2F
6 (''E'' = 0.65 V)
Related reagents
In terms of their properties and applications,
silver tetrafluoroborate
Silver tetrafluoroborate is an inorganic compound with the molecular formula AgBF4. It is a white solid, although commercial samples often are gray, that dissolves in polar organic solvents as well as water.
Preparation
Silver tetrafluoroborate ca ...
(AgBF
4) and the hexafluoroantimonate (AgSbF
6) are similar to AgPF
6.
Comparison with silver nitrate
Silver nitrate
Silver nitrate is an inorganic compound with chemical formula . It is a versatile precursor to many other silver compounds, such as those used in photography. It is far less sensitive to light than the halides. It was once called ''lunar causti ...
is a traditional and less expensive halide abstraction reagent, as indicated by its widespread use in qualitative tests for halides.
Relative to AgPF
6, however, silver nitrate is poorly soluble in weakly basic solvents: the
nitrate
Nitrate is a polyatomic ion with the chemical formula . salt (chemistry), Salts containing this ion are called nitrates. Nitrates are common components of fertilizers and explosives. Almost all inorganic nitrates are solubility, soluble in wa ...
anion is Lewis basic and presents an interfering ligand that precludes its use in stringent applications.
References
{{Fluorine compounds
Silver compounds
Hexafluorophosphates