Octafluorocubane or perfluorocubane is an organofluorine compound with the formula C8F8, consisting of eight carbon atoms joined into a cube, with a fluorine bonded to each carbon corner.

It is a colorless, sublimable solid at room temperature.

It has been of longstanding theoretical interest, but was not synthesised until 2022, when it was prepared in several steps from a cubane carboxylic ester beginning with its heptafluorination.

[1] Octafluorocubane has attracted interest from theorists because of its unusual electronic structure,[2] which is indicated by its susceptibility to undergo reduction to a detectable anion C8F−8, with the free electron trapped inside of the cube.

[3] The compound was voted "favorite molecule of 2022" by readers of Chemical & Engineering News.