UF6 and UF4 in Liquid Ammonia: [UF7(NH3)](3-) and [UF4(NH3)(4)]

作者：Kraus Florian^*; Baer Sebastian A

来源：Chemistry - A European Journal, 2009, 15(33): 8269-8274.

DOI：10.1002/chem.200901044

• actinides
• density functional calculations
• fluorine
• liquid ammonia
• uranium

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)]center dot NH3) and emerald-green crystals of tetraammine tetrafluorouranium(IV) ammonia (1:1; [UF4(NH3)(4)]center dot NH3). [NH4](3)[UF7(NH3)]center dot 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)]center dot NH3 contains discrete tetraammine tetrafluorouranium(IV) [UF4(NH3)(4)] molecules. [UF4(NH3)(4)]center dot NH3 is not stable at room temperature and forms pastel-green [UP4(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.

• 出版日期2009