Materials Data on Sn9(O2F5)2 by Materials Project
(Sn9O4F9)2F2 crystallizes in the tetragonal P4/n space group. The structure is two-dimensional and consists of two hydrofluoric acid molecules and one Sn9O4F9 sheet oriented in the (0, 0, 1) direction. In the Sn9O4F9 sheet, there are three inequivalent Sn2+ sites. In the first Sn2+ site, Sn2+ is bonded in a distorted T-shaped geometry to one O2- and two F1- atoms. The Sn–O bond length is 2.15 Å. There are one shorter (2.13 Å) and one longer (2.26 Å) Sn–F bond lengths. In the second Sn2+ site, Sn2+ is bonded in a distorted rectangular see-saw-like geometry to three equivalent O2- and one F1- atom. There are a spread of Sn–O bond distances ranging from 2.24–2.28 Å. The Sn–F bond length is 2.57 Å. In the third Sn2+ site, Sn2+ is bonded in a distorted square pyramidal geometry to five F1- atoms. There are one shorter (2.03 Å) and four longer (2.67 Å) Sn–F bond lengths. O2- is bonded to four Sn2+ atoms to form distorted edge-sharing OSn4 tetrahedra. There are three inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted linear geometry to two Sn2+ atoms. In the second F1- site, F1- is bonded in a distorted water-like geometry to two Sn2+ atoms. In the third F1- site, F1- is bonded in a single-bond geometry to one Sn2+ atom.