MOLECULAR-STRUCTURES OF SULFUR CYANIDE TRIFLUORIDE, SF3CN, AND SULFINYL CYANIDE FLUORIDE, FS(O)CN

General valence force fields for SF3CN and FS(O)CN are derived from vi brational data taken from the literature and from theoretical calculat ions. Gas phase electron diffraction;studies on both molecules yield t he following geometric parameters (r(a) distances and angles with 3 si gma uncertainties). SF3CN: r(S-F-e) = 155.2(4) r(S-F-a) = 165.7(3), r( S-C)= 173.6(8), r(C=N) = 115.9(4) pm; angle(FaSFe) = 86.9(3), angle(Fa SC) = 86.0(4) angle(FeSC) = 98.7(8), angle(FaSFa) = 169.0(6), angle(SC N) = 171(4)degrees. FS(O)CN: r(S-F) = 159.8(3), r(S=O) = 143.2(2), r(S -C) = 178.3(3), r(C=N) = 115.0(3) pm; angle(FSO) = 104.9(4), angle(FSC ) = 93.9(4), angle(CSO) = 105.3(5), angle(SCN) = 176(4)degrees. These experimental results are compared to ab initio values (HF/3-21G, HF/6 -31G, and MP2/6-31G*), and the bonding properties in these sulfur (IV ) cyanides are discussed.