Atomic structure and bonding in fluorinated graphite intercalated with a strong fluoroxidant.

Intercalation compounds of fluorinated graphite that form when graphite interacts with a strong fluorinating agent have been known for several decades. However, there was not enough understanding about their structures and outstanding stabilities, given that guest molecules contained in them are very active fluoroxidants. In this study, we build a structural model of an ordered crystal of the stage-II intercalation compound C 2 F∙xClF 3 basing on the chain model of the C 2 F layers. The constructed model explains well the experimentally observed composition of the product of gas-phase fluorination of natural graphite (C 2 F∙0.13ClF 3). Experimental X-ray diffraction patterns of the C 2 F∙xClF 3 compound were studied using the constructed models. Phase composition, crystal structure parameters and sizes of ordered regions were refined. The results show that in the C 2 F∙xClF 3 compound every second or third gap between the C 2 F layers is filled with guest molecules, but ordered regions are nanosized, and an amorphous disordered phase exists as well. Noncovalent bonding interactions between the components of the compound (C 2 F...ClF 3 , C 2 F...C 2 F) were examined using topological analysis of the electron density distribution in the framework of Bader's quantum theory, followed by evaluation of the interaction energies. The calculated characteristics prove that the intercalation of ClF 3 molecules into the C 2 F interlayer space is an energetically favorable process. [Display omitted] • Structural models for crystals of an intercalation compound of F-graphite are built; • The geometry is such that the guest is "locked" between the carbon‑fluorine chains; • Cage-like structure explains long-term stability of the compound with a reactive guest; • Guest–host interactions are of noncovalent nature; • Intercalation of ClF 3 into C 2 F is energetically favorable. [ABSTRACT FROM AUTHOR]