THE OXOTRIFLUOROXENON(VI) CATION - X-RAY CRYSTAL-STRUCTURE OF XEOF3+SBF6- AND A SOLUTION O-17 AND XE-129 NUCLEAR-MAGNETIC-RESONANCE STUDY OF THE O-17, O-18-ENRICHED XEOF3+ CATION

The crystal structure of XeOF3+SbF6- has been determined. The compound crystallized in the triclinic system with a = 8.568 (2) angstrom, b = 9.760 (2) angstrom, c = 10. 104 (2) angstrom, alpha = 109.68 (2)-degrees, beta = 92.58 (2)-degrees, gamma = 104.27 (2)-degrees, V = 763.4 angstrom3, and D(calc) = 3.829 g cm-3 for Z = 4. The structure has been refined in the space group P1BAR to a final conventional R factor of 0.045 for 1782 independent reflections with I greater-than-or-equal-to 2.5 sigma(I). The structure consists of XeOF3+SbF6- units with two close contacts between the Xe atom of the cation and F atoms of two SbF6- anions. The isolated XeOF3+ cation is shown to be consistent with the VSEPR rules and to possess an AX4E arrangement of the four bond pair domains and the lone pair domain which give rise to a disphenoid-shaped cation having two longer axial Xe-F(ax) bonds and an Xe-0 bond which is coplanar with the shorter equatorial Xe-F(eq) bond and xenon. Oxygen-17 and -18 enrichment of the XeOF3+cation in HF and SbF5 solvents has allowed the determination of the O-17 chemical shift and 1J(Xe-129-O-17), as well as the O-16, O-18 induced secondary isotopic shift in the Xe-129 NMR spectrum for the first time.