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Title: Solution 31 P NMR Study of the Acid-Catalyzed Formation of a Highly Charged {U 24 Pp 12 } Nanocluster, [(UO 2 ) 24 (O 2 ) 24 (P 2 O 7 ) 12 ] 48– , and Its Structural Characterization in the Solid State Using Single-Crystal Neutron Diffraction

Authors:
 [1];  [2];  [2];  [3];  [3];  [2];  [4];  [1];  [5]
  1. Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
  2. Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana 46556, United States
  3. Chemical and Engineering Materials Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
  4. Instrument and Source Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
  5. Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States; Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana 46556, United States
Publication Date:
Research Org.:
Energy Frontier Research Centers (EFRC) (United States). Materials Science of Actinides (MSA)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1387908
DOE Contract Number:
SC0001089
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of the American Chemical Society; Journal Volume: 138; Journal Issue: 27; Related Information: MSA partners with University of Notre Dame (lead); University of California, Davis; Florida State University; George Washington University; University of Michigan; University of Minnesota; Oak Ridge National Laboratory; Oregon state University; Rensselaer Polytechnic Institute; Savannah River National Laboratory
Country of Publication:
United States
Language:
English
Subject:
nuclear (including radiation effects), materials and chemistry by design, synthesis (novel materials), synthesis (self-assembly)

Citation Formats

Dembowski, Mateusz, Olds, Travis A., Pellegrini, Kristi L., Hoffmann, Christina, Wang, Xiaoping, Hickam, Sarah, He, Junhong, Oliver, Allen G., and Burns, Peter C. Solution 31 P NMR Study of the Acid-Catalyzed Formation of a Highly Charged {U 24 Pp 12 } Nanocluster, [(UO 2 ) 24 (O 2 ) 24 (P 2 O 7 ) 12 ] 48– , and Its Structural Characterization in the Solid State Using Single-Crystal Neutron Diffraction. United States: N. p., 2016. Web. doi:10.1021/jacs.6b04028.
Dembowski, Mateusz, Olds, Travis A., Pellegrini, Kristi L., Hoffmann, Christina, Wang, Xiaoping, Hickam, Sarah, He, Junhong, Oliver, Allen G., & Burns, Peter C. Solution 31 P NMR Study of the Acid-Catalyzed Formation of a Highly Charged {U 24 Pp 12 } Nanocluster, [(UO 2 ) 24 (O 2 ) 24 (P 2 O 7 ) 12 ] 48– , and Its Structural Characterization in the Solid State Using Single-Crystal Neutron Diffraction. United States. doi:10.1021/jacs.6b04028.
Dembowski, Mateusz, Olds, Travis A., Pellegrini, Kristi L., Hoffmann, Christina, Wang, Xiaoping, Hickam, Sarah, He, Junhong, Oliver, Allen G., and Burns, Peter C. 2016. "Solution 31 P NMR Study of the Acid-Catalyzed Formation of a Highly Charged {U 24 Pp 12 } Nanocluster, [(UO 2 ) 24 (O 2 ) 24 (P 2 O 7 ) 12 ] 48– , and Its Structural Characterization in the Solid State Using Single-Crystal Neutron Diffraction". United States. doi:10.1021/jacs.6b04028.
@article{osti_1387908,
title = {Solution 31 P NMR Study of the Acid-Catalyzed Formation of a Highly Charged {U 24 Pp 12 } Nanocluster, [(UO 2 ) 24 (O 2 ) 24 (P 2 O 7 ) 12 ] 48– , and Its Structural Characterization in the Solid State Using Single-Crystal Neutron Diffraction},
author = {Dembowski, Mateusz and Olds, Travis A. and Pellegrini, Kristi L. and Hoffmann, Christina and Wang, Xiaoping and Hickam, Sarah and He, Junhong and Oliver, Allen G. and Burns, Peter C.},
abstractNote = {},
doi = {10.1021/jacs.6b04028},
journal = {Journal of the American Chemical Society},
number = 27,
volume = 138,
place = {United States},
year = 2016,
month = 6
}
  • The amblygonite-montebrasite series of minerals, common constituents of granitic pegmatites and topaz-bearing granites, show complete solid solution with ideal composition LiAlPO{sub 4}(F, OH). These compounds are ideal for studying F {leftrightarrow} OH solid solution in minerals because natural members of the series generally show little deviation from the ideal composition. In this study, we used powder and single-crystal neutron diffraction and solid-state {sup 6}Li MAS, CP MAS, and REDOR NMR techniques to study the effect of F {leftrightarrow} OH substitution on the series. Lattice parameters refined from single-crystal neutron diffraction data show increasing b and decreasing a, c, and Vmore » with increasing F/(F + OH). The volume is highest for the OH end-member because of the presence of an additional atom (H). The a and c parameters decrease with increasing F/(F + OH) because the O-H vector is close to the a-c plane and the Al-OH/F vectors are approximately parallel to c. Lattice parameters refined from neutron powder diffraction patterns collected at lower T show that thermal contraction increases with F/(F + OH), presumably because the F anion takes up less space than the OH molecule. The results show that the OH/F position is always fully occupied. The H displacement ellipsoid shows little change with occupancy, which obviously corresponds negatively with increasing F/(F + OH). However, the Li displacement ellipsoid becomes extremely large and anisotropic with increasing F fraction. Most of the distortion is associated with the U{sub 3} eigenvalue, which lies between the c and c* directions. U{sub eq} values corresponding to the Li atom show a greater reduction with decreasing temperature than the other atoms. The temperature dependence of Li is the same regardless of F content. Even when extrapolated to absolute zero the Li displacement ellipsoid is very large, which implies a large static disorder. At the montebrasite end of the series, there are five short Li- (= O, OH, F) distances and one very long Li-O4 bond. With increasing F content, the Li-O4 distance decreases and the Li-O3f distance increases, such that at the amblygonite end, the coordination is 4 + 2. The disorder in the Li site is obviously caused by the substitution of F for OH. The driving force is the loss of the hydrogen bond to O4, which causes the Li-O4 bond to strengthen and improves the bond valence to O4. The results show that the H atom position is imbedded within the distorted octahedral oxygen coordination of the Li atom. To represent the disorder better, we used a split Li site model. The results show that Li1 occupancy increases and the Li2 occupancy decreases with increasing F content, and that the Li1-Li2 distance is longer for intermediate compositions than for the end-members. The {sup 6}Li MAS NMR experiments provide important structural information complementary to the neutron diffraction results. The spectra of samples in the amblygonite-montebrasite series show two well-resolved peaks, confirming the presence of Li disorder over two distinct sites, and highly resolved {sup 6}Li MAS NMR spectra are obtained at the very high magnetic field strength of 18.8 T. The peaks at -0.3 ppm and -0.9 ppm were unambiguously assigned to the Li2(OH) and Li1(F) sites found in the neutron diffraction structures. The isotropic chemical shifts are consistent with the coordinations of these Li sites found in the neutron diffraction structures. The relative intensities of the two peaks across the series of samples reflect the varying F/(F + OH). In addition to confirming the assignments of the peaks, it is possible to measure H-Li2 and F-Li1 internuclear distances by {sup 6}Li({sup 1}H) and {sup 6}Li({sup 19}F) CP and REDOR NMR that are consistent with the corresponding distances from the neutron diffraction structures. The {sup 6}Li({sup 1}H) and {sup 6}Li({sup 19}F) CP and REDOR results indicate that the Li disorder is random throughout the crystals rather than over large domains, a conclusion that cannot be made from diffraction experiments. Variable temperature {sup 6}Li MAS NMR spectra confirm that the disorder is static and there is no dynamic exchange involving F, OH, or Li. Each Li ion has access to only one of the two observed sites as determined by the presence of either OH or F in its immediate environment and there is no possibility of a dynamic exchange.« less
  • The amblygonite-montebrasite series of minerals, common constituents of granitic pegmatites and topaz-bearing granites, show complete solid solution with ideal composition LiAlPO{sub 4}(F, OH). These compounds are ideal for studying F {leftrightarrow} OH solid solution in minerals because natural members of the series generally show little deviation from the ideal composition. In this study, we used powder and single-crystal neutron diffraction and solid-state {sup 6}Li MAS, CP MAS, and REDOR NMR techniques to study the effect of F {leftrightarrow} OH substitution on the series. Lattice parameters refined from single-crystal neutron diffraction data show increasing b and decreasing a, c, and Vmore » with increasing F/(F + OH). The volume is highest for the OH end-member because of the presence of an additional atom (H). The a and c parameters decrease with increasing F/(F + OH) because the O-H vector is close to the a-c plane and the Al-OH/F vectors are approximately parallel to c. Lattice parameters refined from neutron powder diffraction patterns collected at lower T show that thermal contraction increases with F/(F + OH), presumably because the F anion takes up less space than the OH molecule. The results show that the OH/F position is always fully occupied. The H displacement ellipsoid shows little change with occupancy, which obviously corresponds negatively with increasing F/(F + OH). However, the Li displacement ellipsoid becomes extremely large and anisotropic with increasing F fraction. Most of the distortion is associated with the U{sub 3} eigenvalue, which lies between the c and c* directions. U{sub eq} values corresponding to the Li atom show a greater reduction with decreasing temperature than the other atoms. The temperature dependence of Li is the same regardless of F content. Even when extrapolated to absolute zero the Li displacement ellipsoid is very large, which implies a large static disorder.« less
  • It has been demonstrated, for the first time by diffraction methods, that a solid solution composed of host and guest molecules can exhibit a crystal symmetry lower than that of the host. The study proves that the symmetry of a solid solution is dependent not only upon the host crystal structure and the guest molecular structure but also upon the surface structure and symmetry of the host crystal. The crystal structures of (S)-asparagine monohydrate (D{sub 2}NCOCH{sub 2}CH(ND{sub 3})CO{sub 2} {times} D{sub 2}O) and of the solid solution (0.848:0.152) (S)-asparagine/(S)-aspartic acid (DO{sub 2}CCD{sub 2}CD(ND{sub 3})CO{sub 2}) monohydrate were refined by usingmore » neutron diffraction data obtained at 15 K. The space group of the pure host crystal is P2{sub 1}2{sub 1}2{sub 1} (Z = 4), whereas that of the host/guest crystal is monoclinic P12{sub 1}1 with two molecular sites per asymmetric unit. The ratios of guest/host occupancies of the two independent sites are 0.173:0.827 and 0.132:0.868. The reduction in symmetry is in accordance with the preferred adsorption of guest aspartic acid on the (010) crystal face at half of the orthorhombic, symmetry-related surface sites. Aspartic acid mimics, at the preferred (010) surface sites, molecular asparagine, participating in all hydrogen bonds. At the less-favored (010) surface sites a normal N-H{hor ellipsis}O(host) hydrogen bond is replaced by O(hydroxyl){hor ellipsis}O(host) repulsion between lone-pair electrons. 21 refs., 5 figs., 6 tabs.« less
  • The structure of lithium zirconate (Li[sub 6]Zr[sub 2]O[sub 7]) has been solved by the single-crystal X-ray method. Li[sub 6]Zr[sub 2]O[sub 7] is monoclinic, space group C2/c and cell parameters a = 10.440(4), b = 5.991(1), c = 10.204(2) [angstrom], [beta] = 100.25(3)[degrees], Z = 8 (for the asymmetric unit Li[sub 3]ZrO[sub 7/2]). A least-squares refinement gave conventional and weighted R factors of 0.041 and 0.052, respectively. The structure is of the NaCl type and is characterized by an ordered anionic deficiency. As a consequence the coordination number of the Li atoms is 5, with the coordination geometry of a distortedmore » square pyramid. Also, the oxygen octahedron around each Zr atom is significantly distorted. A comparison between Li[sub 6]Zr[sub 2]O[sub 7] and Li[sub 2]ZrO[sub 3], another phase of the NaCl type, shows that the structure of the former compound is more [open quotes]open[close quotes] than that of Li[sub 2]ZrO[sub 3] and, for this reason, a higher mobility of both the Li[sup +] and O[sup 2[minus]] ions can be expected for the former phase. These results are in agreement with conductivity measurements. 10 refs., 2 figs., 6 tabs.« less