UF6 and UF4 in liquid ammonia: [UF7(NH3)]3- and [UF4(NH3)4].
UF6 and UF4 in liquid ammonia: [UF7(NH3)]3- and [UF4(NH3)4].
复制标题
液氨中的UF6和UF4：[UF7(NH3)]3-和[UF4(NH3)4]。
作者：
F. Kraus;S. Baer
从六氟化铀UF6与干液氨的反应中，首次分离和鉴定了[UF7(NH3)]3-离子和[UF4(NH3)4]分子。它们存在于七氟尿酸三铵单胺(IV)氨(1：1；[NH_4]_3[UF_7(NH_3)]·NH_3)和四胺四氟铀(IV)氨(1：1；[UF_4(NH_3)_4]·NH_3)的翠绿色晶体中。[NH4]3[UF7(NH3)].NH3具有离散的[UF7(NH3)]3-阴离子，其配位构型类似于双冠三棱柱，这在U(IV)化合物中是未知的。翡翠绿色的[UF4(NH3)4].NH3含有离散的四胺四氟铀(IV)[UF4(NH3)4]分子。[UF4(NH3)4].NH3在室温下不稳定，形成淡绿色[UF4(NH3)4]粉末，其稳定性高达147℃。这些化合物是第一个对氟化铀的氨络合物进行结构表征的化合物。
From the reaction of uranium hexafluoride UF6 with dry liquid ammonia, the [UF7(NH3)]3- anion and the [UF4(NH3)4] molecule were isolated and identified for the first time. They are found in signal-green crystals of trisammonium monoammine heptafluorouranate(IV) ammonia (1:1; [NH4]3[UF7(NH3)].NH3) and emerald-green crystals of tetraammine tetrafluorouranium(IV) ammonia (1:1; [UF4(NH3)4].NH3). [NH4]3[UF7(NH3)].NH3 features discrete [UF7(NH3)]3- anions with a coordination geometry similar to a bicapped trigonal prism, hitherto unknown for U(IV) compounds. The emerald-green [UF4(NH3)4].NH3 contains discrete tetraammine tetrafluorouranium(IV) [UF4(NH3)4] molecules. [UF4(NH3)4].NH3 is not stable at room temperature and forms pastel-green [UF4(NH3)4] as a powder that is surprisingly stable up to 147 degrees C. The compounds are the first structurally characterized ammonia complexes of uranium fluorides.