In haloalkanes and haloarenes (), Halogen functional groups are prefixed with the bonding position and take the form of fluoro-, chloro-, bromo-, iodo-, etc., depending on the halogen. Multiple groups are dichloro-, trichloro-, etc., and dissimilar groups are ordered alphabetically as before. For example,  (chloroform) is trichloromethane. The anesthetic halothane () is 2-bromo-2-chloro-1,1,1-trifluoroethane.