text: Chlorine and bromine reversibly intercalate into graphite. Iodine does not. Fluorine reacts irreversibly. In the case of bromine, the following stoichiometries are known:  for n = 8, 12, 14, 16, 20, and 28.
  Because it forms irreversibly, carbon monofluoride is often not classified as an intercalation compound. It has the formula . It is prepared by reaction of gaseous fluorine with graphitic carbon at 215–230 °C. The color is greyish, white, or yellow. The bond between the carbon and fluorine atoms is covalent. Tetracarbon monofluoride () is prepared by treating graphite with a mixture of fluorine and hydrogen fluoride at room temperature. The compound has a blackish-blue color. Carbon monofluoride is not electrically conductive. It has been studied as a cathode material in one type of primary (non-rechargeable) lithium batteries.
  Graphite oxide is an unstable yellow solid.