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Topic Name: X-ray scattering techniques
Category: Chemical
Research persons: L. Soderholm,S. Skanthakumar,Richard E. Wilson
Location: Argonne National Laboratory,9700 S. Cass Avenue,Argonne, IL 60439.,Phone: 630/252-2000, United States
Details
Researchers at
the Department of Energy's Argonne National Laboratory and the University of
Notre Dame have successfully applied X-ray scattering techniques to determine
how dissolved metal ions interact in solution.These findings will help
researchers better understand how metal ions, such as those found in nuclear
waste and other industrial processes, behave in the environment.The results show
that the ion structures are visible in solution and reveals their interactions
with other ions. "The scientific
community has long asked the question,'What happens to a metal ion in
solution?'” said Suntharalingam “Skantha” Skanthakumar, Argonne senior
scientific associate. "Direct measurement of metal correlations in solutions
show long-range interactions and a strong correspondence to the structures in
solution and solid state environment.""We have been
provided with additional structural and chemical insight into tetravalent
actinide hydrolysis," said Lynda Soderholm. "We discovered that the way atoms
interact is transferable with a lot more detail than what was previously
thought. Hydrolysis of dissolved metal ions is one of the most fundamental and
important reactions in aqueous chemistry.”Experiments for
this work were conducted at Argonne's Advanced
Photon Source (APS). The 1,104-meter circumference APS accelerator complex,
large enough to encircle a baseball stadium, houses a complex of machines and
devices that produce, accelerate and store a beam of electrons that is the
source of the APS X-rays. For this research, thin beams of high-energy X-rays
were used to bombard the dissolved ions. When the X-rays scattered off the
solutions, special CCD cameras equipped to detect them mapped out their
two-dimensional pattern.The detailed
results of these findings were published in the paper "Structures of Dimeric
Hydrolysis Products of Thorium" and in the journal
Inorganic Chemistry."Going forward,
additional research is planned with thorium and other dissolvable materials
across the periodic table," said Argonne postdoctoral researcher Richard E.
Wilson. "The goal is to be able to predict reactions to metal contaminants and
determine the chemistry that influences their transport in the environment"This research
involved collaborations from various scientific disciplines including input from
physicists, chemists and geologists. Collaborators on this research were Richard
E. Wilson, S. Skanthakumar, and Lynda Soderholm from Argonne, and Peter Burns
and Ginger Sigmon from the University of Notre Dame.
The nation's
first national laboratory, Argonne National Laboratory conducts basic and
applied scientific research across a wide spectrum of disciplines, ranging from
high-energy physics to climatology and biotechnology. Since 1990, Argonne has
worked with more than 600 companies and numerous federal agencies and other
organizations to help advance America's scientific leadership and prepare the
nation for the future. Argonne is managed by
UChicago Argonne,
LLC for the U.S. Department
of Energy's
Office of Science
Abstract:
Three unique
thorium dimeric compounds have been crystallized from either direct hydrolysis
of Th4+(aq)/HCl or titration of Th(OH)4(am) with Th(NO3)4(aq)
and their structures determined using single-crystal X-ray diffraction. The
compound [Th2( 2-OH)2(NO3)6(H2O)6]H2O
(1) is identical to that identified previously by Johansson. Two
additional unreported compounds have been identified, [Th2(2-OH)2(NO3)4(H2O)8](NO3)2
(2) and [Th2(2-OH)2Cl2(H2O)12]Cl4·2H2O
(3). 1 crystallizes in the monoclinic space group P21/c,
with a = 6.792(2) Å, b = 11.710(4) Å, c = 13.778(5) Å, and
= 102.714(5)
and 2 crystallizes in the monoclinic space group P21/n,
with a = 6.926(5) Å, b = 7.207(1) Å, c = 21.502(1) Å, and
= 96.380(1).
The chloride-containing dimer, 3, crystallizes in triclinic P ,
with a = 8.080(2) Å, b = 8.880(2) Å, c = 9.013(2) Å,
= 97.41(3),
= 91.00(3), and
= 116.54(3).
We also present high-energy X-ray scattering data demonstrating the presence of
the hydroxo-bridged moiety in solution and discuss our findings in the context
of known solid-state structures. The three structures demonstrate 11-, 10-, and
9-coordinate thorium, respectively, and coupled with the scattering experiments
provide additional structural and chemical insight into tetravalent actinide
hydrolysis.
About Researcher's :
L.
Soderholm
Lynda Soderholm
(McMaster University, Hamilton, Ontario, Canada) is a
Chemist, the director for the Actinide Facility, Group Leader of f-Electron
Interactions, and co-recipient of a DOE Materials Science Research Competition
for Outstanding Scientific Accomplishments in Solid State Physics. Her research
interests include solid state synthesis and the characterization of f-element
compounds, their electronic properties and their influence on structural,
magnetic,
and conducting properties, including the high-Tc superconductors.
Contact information:
| Chemistry Division |
 |
Phone |
|
630/252-4364 |
| Argonne National Laboratory |
|
Email |
|
LS@anl.gov
|
| Argonne, IL 60439 |
|
Fax: |
|
630/252-9289 |
S.
Skanthakumar
Education
B.Sc (Hons) in
Physics, University of Peradeniya,
Peradenyia, Sri Lanka (1984) ,PhD in Physics, University of Maryland, College
Park (1993) ,Ph.D thesis adviser: Jeff
Lynn
Experimental Techniques:
Neutron scattering X-Ray
diffraction and absorption
Physics Research:
High Tc Superconductors Magneto
resistive materials Magnetism
Contact information:
| Suntharalingam Skanthakumar is in the
Chemistry |
|
Phone |
|
(630) 252-1754 |
| Division of Argonne National Laboratory |
|
Email |
|
skantha@anl.gov |
| Building 200 - M153 ,Argonne, IL 60439, U.S.A |
|
Fax |
|
(630)
252-4225 |
Richard E. Wilson
Contact information:
| Suntharalingam Skanthakumar is in the
Chemistry |
|
Phone |
|
630-252-1288 |
| Division of Argonne National Laboratory |
|
Email |
|
rewilson@anl.gov |
| Bldg. 200, M167,Argonne, IL 60439 |
|
Fax |
|
(630-252-4225
|
Funded :
Funding for this
project was provided by DOE's Office of
Basic
Energy Sciences, and Division of
Chemical Sciences, Geosciences, and Biosciences.
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