The [U2 F12 ]2- Anion of Sr[U2 F12 ].

The D2h -symmetric dinuclear complex anion [U2 F12 ]2- of pastel green Sr[U2 F12 ] shows a hitherto unknown structural feature: The coordination polyhedra around the U atoms are edge-linked monocapped trigonal prisms, the UV atoms are therefore seven-coordinated. This leads to a U-U distance of 3.8913(6) Å. A weak UV -UV interaction is observed for the dinuclear [U2 F12 ]2- complex and described by the antiferromagnetic exchange Jexp of circa -29.9 cm-1 . The crystalline compound can be easily prepared from SrF2 and β-UF5 in anhydrous hydrogen fluoride (aHF) at room temperature. It was studied by means of single crystal X-ray diffraction, IR, Raman and UV/VIS spectroscopy, magnetic measurements, and by molecular as well as by solid-state quantum chemical calculations.