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 (ReF₇), and gold heptafluoride (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. ...

of gold pentafluoride (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 ...

. Many dimeric and oligomeric heptafluorides have been observed or proposed. One example is B₂F₇⁻. In the area of organofluorine chemistry, many heptafluorides are known. A prominent example is heptafluorobutyric acid. This species and its conjugate base heptafluorobutyrate (C₃F₇CO₂⁻) are precursors to surfactants.

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