Miskowiec Andrew, Kirkegaard Marie C, Huq Ashfia, Mamontov Eugene, Herwig Kenneth W, Trowbridge Lee, Rondinone Adam, Anderson Brian
Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.
University of Tennessee - Knoxville , Knoxville, Tennessee 37996, United States.
J Phys Chem A. 2015 Dec 10;119(49):11900-10. doi: 10.1021/acs.jpca.5b09296. Epub 2015 Nov 24.
We report a novel production method for uranium oxyfluoride [(UO2)7F14(H2O)7]·4H2O, referred to as structure D. Structure D is produced as a product of hydrating anhydrous uranyl fluoride, UO2F2, through the gas phase at ambient temperatures followed by desiccation by equilibration with a dry environment. We follow the structure of [(UO2)7F14(H2O)7]·4H2O through an intermediate, liquid-like phase, wherein the coordination number of the uranyl ion is reduced to 5 (from 6 in the anhydrous structure), and a water molecule binds as an equatorial ligand to the uranyl ion. Quasielastic neutron scattering results compare well with previous measurements of mineral hydrates. The two groups of structurally distinct water molecules in D perform restricted motion on a length scale commensurate with the O-H bond (r = 0.92 Å). The more tightly bound equatorial ligand waters rotate slower (Dr = 2.2 ps(-1)) than their hydrogen-bonded partners (Dr = 28.7 ps(-1)).
我们报道了一种制备氟氧化铀[(UO2)7F14(H2O)7]·4H2O（称为结构D）的新方法。结构D是通过在环境温度下使无水氟化铀酰UO2F2在气相中进行水合，然后与干燥环境平衡进行干燥而制备得到的。我们通过一个类似液体的中间相追踪[(UO2)7F14(H2O)7]·4H2O的结构，其中铀酰离子的配位数从无水结构中的6降低到5，并且一个水分子作为赤道配体与铀酰离子结合。准弹性中子散射结果与先前对矿物水合物的测量结果吻合良好。D中两组结构不同的水分子在与O - H键相当的长度尺度（r = 0.92 Å）上进行受限运动。与氢键结合的伙伴（Dr = 28.7 ps(-1)）相比，结合更紧密的赤道配体水旋转较慢（Dr = 2.2 ps(-1)）。
