The nature of fluorine in amorphous silica

Abstract We have used solid-state nuclear magnetic resonance spectroscopy and molecular dynamics simulations to characterize the short-range structure of fluorine-doped silica glass. The fluorine atoms in a glass containing 3 wt% fluorine are found in two different structural environments. The most abundant of these is a fluorine atom bonded to a tetrahedral silicon atom, where the fluorine has replaced one of the bridging oxygens and formed the usual Q3 species. The second, and less abundant of these fluorine types, originates from fluorine bonded to a silicon atom with four bridging oxygen atoms, ultimately giving rise to a fivefold coordinated silicon atom. Additional insight into these Si–F bonding configurations was obtained in the simulation results.