Heptafluoride
Heptafluoride typically refers to compounds with the formula RMF or RMF, where n, x, and y are independent variables and R any substituent. Binary heptafluorides. The only binary heptafluorides are iodine heptafluoride (IF), rhenium heptafluoride (ReF), and gold heptafluoride (AuF). Only IF and ReF are true heptafluorides, however, as AuF is actually a coordination complex of gold pentafluoride (AuF) and molecular fluorine; therefore, the correct chemical formula of gold heptafluoride is actually AuF·F. Heptafluoride anions. A commercially important heptafluoride anion is the heptafluorotantalate anion, TaF. It is an intermediate in the purification of tantalum. Many dimeric and oligomeric heptafluorides  have been observed or proposed. One example is BF. In the area of organofluorine chemistry, many heptafluorides are known. A prominent example is heptafluorobutyric acid. This species and its conjugate base heptafluorobutyrate (CFCO) are precursors to surfactants. Complex heptafluorides. Many compounds that are not discrete ions or molecules also are heptafluorides.