Crystal structures of pentafluoroxenon(1+) tetrafluorometallate(1-) (metal = silver, gold) and their relevance to the basicity and oxidizability of tetrafluorometallate(1-)

• DOI: 10.1021/ic00317a014
• Publication Date: 2005-03-10T06:21:54Z
• Authors: Karel Lutar; Adolf Jesih; Ivan Leban; Boris Zemva; Neil Bartlett
• Keywords: 01 natural sciences; 0104 chemical sciences

XeF{sub 5}{sup +}AuF{sub 4}{sup {minus}} has been prepared from BrF{sub 3}{center dot}AuF{sub 3} by displacement of BrF{sub 3} with XeF{sub 6}. The salt interacts quantitatively with KrF{sub 2} in anhydrous HF, below 0{degree}C, to yield XeF{sub 5}{sup +}AuF{sub 6}{sup {minus}}. XeF{sub 5}AuF{sub 4} (I) is isostructural with XeF{sub 5}AgF{sub 4} (II), and these compounds crystallize in space group I4/m with the following unit cell dimensions: I, a{sub 0} = 5.735 (5) {angstrom}, c{sup 0} = 20.007 (17) {angstrom}, V = 658 (2) {angstrom}{sup 3}, Z = 4; II, a{sub 0} = 5.593 (2) {angstrom}, c{sub 0} = 20.379 (5) {angstrom}, V = 637.5 (8) {angstrom}{sup 3}, Z = 4. The structure of II was solved by the Patterson method and refined to conventional R and R{sub W} values of 0.077 and 0.090, respectively. The structure contains double layers of XeF{sub 5}{sup +} and layers of AgF{sub 4}{sup {minus}} ions, all layers being parallel to the ab plane. The XeF{sub 5}{sup +} ion had C{sub 4{sigma}} symmetry with Xe-F(axial) = 1.853 (19) {angstrom}, Xe-F(equatorial) = 1.826 (9) {angstrom}, and F(axial)-Xe-F(equatorial) = 77.7 (3){degree}. The anion (site symmetry D{sub 2h}), which is not significantly different from D{sub 4h} symmetry, has Ag-F =more » 1.902 (11) {angstrom}. Differences between the XeF{sub 5}AgF{sub 4} and XeF{sub 5}AuF{sub 4} structures are attributed to lower ligand charges in the anion of the former, relative to those in the latter, and these in turn are related to observed differences in the basicity and oxidizability of the anions. 24 refs., 5 figs., 4 tabs.« less