Kashtiban, Reza J.Dyson, M. AdamNair, Rahul R.Zan, RecepWong, Swee L.Ramasse, QuentinGeim, Andre K.2024-11-072024-11-0720142041-1723https://doi.org/10.1038/ncomms5902https://hdl.handle.net/11480/16442One of the most desirable goals of graphene research is to produce ordered two-dimensional (2D) chemical derivatives of suitable quality for monolayer device fabrication. Here we reveal, by focal series exit wave reconstruction (EWR), that C2F chair is a stable graphene derivative and demonstrates pristine long-range order limited only by the size of a functionalized domain. Focal series of images of graphene and C2F chair formed by reaction with XeF2 were obtained at 80 kV in an aberration-corrected transmission electron microscope. EWR images reveal that single carbon atoms and carbon-fluorine pairs in C2F chair alternate strictly over domain sizes of at least 150 nm(2) with electron diffraction indicating ordered domains >= 0.16 mu m(2). Our results also indicate that, within an ordered domain, functionalization occurs on one side only as theory predicts. In addition, we show that electron diffraction provides a quick and easy method for distinguishing between graphene, C2F chair and fully fluorinated stoichiometric CF 2D phases.eninfo:eu-repo/semantics/openAccessResolutionReconstructionFluorographeneArticle510.1038/ncomms5902252232262-s2.0-84923372363Q1WOS:000342983700009Q1