TY - JOUR
T1 - Structural Phase Transitions and Water Dynamics in Uranyl Fluoride Hydrates
AU - Miskowiec, Andrew
AU - Kirkegaard, Marie C.
AU - Huq, Ashfia
AU - Mamontov, Eugene
AU - Herwig, Kenneth W.
AU - Trowbridge, Lee
AU - Rondinone, Adam
AU - Anderson, Brian
N1 - Publisher Copyright:
© 2015 American Chemical Society.
PY - 2015/12/10
Y1 - 2015/12/10
N2 - 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).
AB - 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).
UR - http://www.scopus.com/inward/record.url?scp=84948952213&partnerID=8YFLogxK
U2 - 10.1021/acs.jpca.5b09296
DO - 10.1021/acs.jpca.5b09296
M3 - Article
AN - SCOPUS:84948952213
SN - 1089-5639
VL - 119
SP - 11900
EP - 11910
JO - Journal of Physical Chemistry A
JF - Journal of Physical Chemistry A
IS - 49
ER -