Noble molecule: [Mg(XeF(2))(XeF(4))](AsF(6))(2) is the first coordination compound in which XeF(4) acts as a ligand to a metal center. It is also the first known compound, in which XeF(2) and XeF(4) are simultaneously coordinated to the same metal center (see structure; purple Xe, green F, gray Mg, yellow As).