The 119Sn Mössbauer and solid-state NMR and the crystal and molecular structure of tin(II) bisfluorosulfate, Sn(OSO2F)2

Abstract

The reaction of tin(II) fluoride with fluorosulfuric acid has been shown to produce tin(II) bisfluorosulfate. Crystals of Sn(OSO2F)2 are monoclinic, space group P21/c with a = 5.195(1), b = 9.709(1), c = 13.861(1) Å, β = 110.12(1)°, Z = 4, R = 0.029, and Rw = 0.030 for 1461 unique reflections. The structure consists of a three-dimensional framework of fluorosulfate groups linked by O—Sn—O bridges with the two crystallographically independent fluorosulfates acting as tridentate bridging ligands between tin atoms. There are four short bonds (Sn—O = 2.338(3), 2.350(3), 2.398(4), and 2.427(3) Å) and two longer ones (Sn—O = 2.695(3) and 2.702(3) Å) around tin. The four short bonds have a disphenoidal, AX4E, primary geometry with the lone pair occupying an equatorial site. If the two longer interactions are also considered the geometry is distorted octahedral, AX4Y2E. Two more non-bonding contacts of 3.420(4) and 3.319(4) Å complete an approximately dodecahedral arrangement of oxygen atoms around the tin. The fluorosulfate groups deviate significantly from C3υ symmetry and have the mean dimensions, S(1)—O = 1.419(4), S(1)—F = 1.541(4), S(2)—O = 1.435(3), S(2)—F = 1.539(3) Å, O—S(1)—O = 114.3(2)°, F—S(1)—O = 104.1(3)°, O—S(2)—O = 114.2(2)°, and F—S(2)—O = 104.1(2)°, respectively. The solid-state 119Sn nmr spectrum shows only one single resonance with a shift of −1534 ppm which is substantially different from that of a solution in HSO3F. The 119Sn Mössbauer spectrum shows an unresolved quadrupole splitting as a result of a distorted environment around tin, produced by the stereochemically active non-bonding electron pair. Key words: tin(II) bisfluorosulfate, 119Sn Mössbauer, solid-state nmr, X-ray crystallography