Heptafluoride typically refers to compounds with the formula R_nM_x F₇^y− or R_nM_xF₇^y+, where n, x, and y are independent variables and R any substituent.

Binary heptafluorides

The only binary heptafluorides are

iodine heptafluoride Iodine heptafluoride, also known as iodine(VII) fluoride or iodine fluoride, is an interhalogen compound with the chemical formula I F7. It has an unusual pentagonal bipyramidal structure, as predicted by VSEPR theory. The molecule can undergo ...

(IF₇),

rhenium heptafluoride Rhenium heptafluoride is the compound with the formula ReF7. It is a yellow low melting solid and is the only thermally stable metal heptafluoride. It has a distorted pentagonal bipyramidal structure similar to IF7, which was confirmed by neutron ...

(ReF₇), and

gold heptafluoride Gold heptafluoride is a gold(V) compound with the empirical formula AuF7. The synthesis of this compound was first reported in 1986. However, current calculations suggest that the structure of the synthesized molecule was actually a difluorine lig ...

(AuF₇). Only IF₇ and ReF₇ are true heptafluorides, however, as AuF₇ is actually a

coordination complex A coordination complex consists of a central atom or ion, which is usually metallic and is called the ''coordination centre'', and a surrounding array of bound molecules or ions, that are in turn known as ''ligands'' or complexing agents. Many ...

gold pentafluoride Gold(V) fluoride is the inorganic compound with the formula Au2F10. This fluoride compound features gold in its highest known oxidation state. This red solid dissolves in hydrogen fluoride but these solutions decompose, liberating fluorine. Th ...

(AuF₅) and molecular fluorine; therefore, the correct chemical formula of gold heptafluoride is actually AuF₅·F₂.

Heptafluoride anions

A commercially important heptafluoride anion is the heptafluorotantalate anion, TaF₇²⁻. It is an intermediate in the purification of

tantalum Tantalum is a chemical element with the symbol Ta and atomic number 73. Previously known as ''tantalium'', it is named after Tantalus, a villain in Greek mythology. Tantalum is a very hard, ductile, lustrous, blue-gray transition metal that is ...

. Many dimeric and oligomeric heptafluorides have been observed or proposed. One example is B₂F₇⁻. In the area of

organofluorine chemistry Organofluorine chemistry describes the chemistry of the organofluorines, organic compounds that contain the carbon–fluorine bond. Organofluorine compounds find diverse applications ranging from Lipophobicity, oil and hydrophobe, water repellents ...

, many heptafluorides are known. A prominent example is

heptafluorobutyric acid Perfluorobutanoic acid (PFBA) is a perfluoroalkyl carboxylic acid with the formula C3F7CO2H. As the perfluorinated derivative of butyric acid, this colourless liquid is prepared by electrofluorination Electrochemical fluorination (ECF), or elect ...

. This species and its conjugate base heptafluorobutyrate (C₃F₇CO₂⁻) are precursors to

surfactant Surfactants are chemical compounds that decrease the surface tension between two liquids, between a gas and a liquid, or interfacial tension between a liquid and a solid. Surfactants may act as detergents, wetting agents, emulsifiers, foaming ...

Complex heptafluorides

Many compounds that are not discrete ions or molecules also are heptafluorides.Grosse, L.; Hoppe, R. "Zur Kenntnis von Sr₂RhF₇" Zeitschrift für Anorganische und Allgemeine Chemie (1987), 552, 123-31.{{doi, 10.1002/zaac.19875520914

References

Fluorides