The relative fluoride ion donor abilities of XeF₂, XeF₄, and XeF₆ and a chemical purification of XeF₄

XeF4 as a Ligand for a Metal Ion

“…[5] The first coordination compound with a noble-gas fluoride acting as a ligand to a metal ion was [Ag(XeF 2 ) 2 ]AsF 6 . [6] A series of such coordination compounds has since been prepared, [7] but coordination compounds with XeF 4 , (a poorer Lewis base or less thermally stable than XeF 2 [8] ) as a metal ion ligand, were not known.…”

“…At the molar ratio XeF 2 :Mg = 2:1 or higher the only product was [Mg(XeF 2 ) 2 ]-(AsF 6 ) 2 , which is in accord with the lower Lewis basicity of XeF 4 . [8] The magnesium ion is surrounded by six fluorine atoms, four from [AsF 6 ] À units, one from XeF 2 , and one from XeF 4 ( Figure 1 À unit is trans bridging, whereas the [As2F 6 ] À unit is a cis bridging in the complex. In both cases, the bridging As À F distances are elongated.…”

Arsenic, Antimony and Bismuth

“…Yellow arsenic, obtained by sudden cooling of arsenic vapour, is assumed to consist of AS4 molecules. It can be recrystallized from carbon disulphide (solubility: 11 g in 100 ml at 46°C; 4 g at 0°C; 0.8 g at -80°C) but is rapidly converted to grey arsenic in light, and very easily oxidized 5 . Above 300°C, arsenic vapour condenses as grey arsenic, but, at 100-200°C, glassy modifications result.…”

“…The compounds AS2H4, AS2H5 and Sb 2 H 4 have been made only in very low yields, and so information about them is limited 5 <>. The catenated compounds are isolated as byproducts in the preparation of the trihydrides from metal arsenides or antimonides or from borohydride reductions.…”

“…As 111 NNdiethyl-dithiocarbamate As(S2CNEt 2 )3, from arsenic trichloride and sodium diethyl dithiocarbamate, has a structure in which each arsenic atom makes three bonds (As-S, 235 pm) at 90°, and three longer bonds (As-S, 280-290 pm), so that the configuration round arsenic is that of a distorted antiprism 85 . In potassium di-o-phenylenedioxyarsenite [4] each arsenic makes four bonds to the corners of a distorted trigonal bipyramid [5], with equatorial bonds, opposite the lone pair, 180.7 and axial bonds 199.5 pm 86 . A similar configuration at antimony is found in antimony hydrogen bis(thioglycollate) Sb(SCH 2 C0 2 )2H, which has Sb-O (axial) 228, Sb-S (equatorial) 242.8 pm.…”