H. Rojo, A. C. Scheinost, B. Lothenbach, A. Laube, E. Wieland and J. Tits, Dalton Transactions 2018, 47, 4209-4218.
Retention of selenium by concrete barriers
Structure and sorption of an elusive anion, HSe-
HSe- is barely sorbed by most minerals, posing a significant risk for the safe disposal of this long-lived fission product. The cement barrier foreseen for intermediate-level waste repositories, however, contains AFm phases, which due to their anion exchanging properties may be able to retain HSe-1.
Here we could show that HSe- is in fact significantly sorbed in the interlayers of AFm-HC.
HSe- is lesser sorbed by a similar phase, AFm-MC, due to the lesser accessibility of its interlayer space.
A. Amon, A. Ormeci, M. Bobnar, L. G. Akselrud, M. Avdeev, R. Gumeniuk, U. Burkhardt, Y. Prots, C. Hennig, A. Leithe-Jasper and Y. Grin, Accounts of Chemical Research 2018, 51, 214-222. IF 20.3
Cluster formation in the superconducting intermetallic Be21Pt5
Solving the crystal structure of this new superconductor (Tc = 2.1 K)
X-ray diffraction: localization of the heavier Pt atoms
Neutron diffraction: localization of the light Be-atoms (differential Fourier syntheses)
Analysis of chemical bonding in Be21Pt5 by electron localizability indicator (ELI)
TOP: Fundamental understanding of Ln/An (hydr)oxide nanoparticles
successful ERC Grant by Kristina Kvashnina
Press release "Ganz unten im Periodensystem - HZDR-Forscherin erhält millionenschwere Nachwuchsförderung der Europäischen Union"
Gregson, M., Lu, E., Mills, D.P., Tuna, F., McInnes, E.J.L., Hennig, C., Scheinost, A.C., McMaster, J., Lewis, W., Blake, A.J., Kerridge, A. and Liddle, S.T. (2017) The inverse-trans-influence in tetravalent lanthanide and actinide bis(carbene) complexes. Nature Communications 8, 14137. IF 12.1
Principles of chemical bonding:
Trans-configuration a general rule for lanthanides and actinides?
Butorin, S.M, Kvashnina, K.O., Prieur, D., Rivenet, M., Martin, P.M. (2017) Chem. Comm. 53, 115.
Towards the safe disposal of spent nuclear fuel:
Charge compensation mechanisms in Ln-doped UO2
Ln-doped UO2 as model for spent nuclear fuel with lanthanide fission products
High-resolution M4-edge spectroscopy crucial to resolve electronic structure of actinides:
- Charge of LnIII is compensated for by equimolar formation of UV
- Significant change of bond covalency, from Mott-Hubbard in undoped UO2 to U 5f-O 2p hybridization in Ln-doped UO2
Fröhlich, D.R., et al., Inorganic Chemistry, 2017, 56, 6820-6829.
Deciphering Am speciation in presence of formate
Challenge for EXAFS, since small spectroscopic variations (< 9%) in pH-range 2 to 4
Combined DFT and advanced statistical analysis of EXAFS (ITFA):
- confirmed thermodynamic constants
- deciphered structure of the two (monodentate) 1:1 and 1:2 Am-formate complexes
C. Hennig, S.Weiss, W. Kraus, J. Kretzschmar, A. C. Scheinost, Inorg. Chem. 2017, 56, 2473-2480
Solution species and crystal structure of Zr(IV) acetate
The complex formation of zirconium with acetic acid was investigated with Zr K-edge EXAFS
spectroscopy and single crystal diffraction. Zr K edge EXAFS spectra show that a stepwise
increase of acetic acid in aqueous solution with 0.1 M Zr(IV) leads to a structural rearrangement
from initial tetranuclear hydrolysis species [Zr4(OH)8(OH2)16]8+ to a hexanuclear
acetate species Zr6(O)4(OH)4(CH3COO)12.