Hydrothermal synthesis, structure, Raman spectroscopy, and self-irradiation studies of {sup 248}Cm(IO{sub 3}){sub 3}
- Transuranium Research Laboratory, Oak Ridge National Laboratory, Chemical Sciences Division, MS 6375, P.O. Box 2008, Oak Ridge, TN 37831 (United States)
- Department of Chemistry and Leach Nuclear Science Center, Auburn University, 179 Chemistry Building, Auburn, AL 36849 (United States)
The study of curium iodate, Cm(IO{sub 3}){sub 3}, was undertaken as part of a systematic investigation of the 4f- and 5f-elements' iodates. The reaction of {sup 248}CmCl{sub 3} with aqueous H{sub 5}IO{sub 6} under mild hydrothermal conditions results in the reduction of IO{sub 6}{sup 5-} to IO{sub 3}{sup -} anions, and the subsequent formation of Cm(IO{sub 3}){sub 3} single crystals. Crystallographic data are: (193K, MoK{alpha}, {lambda}=0.71073A): monoclinic, space group P2{sub 1}/c, a=7.2014(7)A, b=8.5062(9)A, c=13.4622(14)A, {beta}=100.142(2){sup o}, V=811.76(14), Z=4, R(F)=2.11%, Rw(Fo2)=4.43% for 119 parameters with 1917 reflections with I>2{sigma}(I). The structure consists of Cm{sup 3+} cations bound by iodate anions to form [Cm(IO{sub 3}){sub 8}] units, where the local coordination environment around the curium centers can be described as a distorted dodecahedron. There are three crystallographically unique iodate anions within the structure; two iodates bridge between three Cm centers, and one iodate bridges between two Cm centers and has a terminal oxygen atom. The bridging of the curium centers by the iodate anions creates a three-dimensional structure. Three strong Raman bands with comparable intensities were observed at 846, 804, and 760cm{sup -1} and correspond to the I-O symmetric stretching of the three crystallographically distinct iodate ions. The Raman profile suggests a lack of inter-ionic vibrational coupling of the I-O stretching, while intra-ionic coupling provides symmetric and asymmetric components that correspond to each iodate site. Repeated collection of X-ray diffraction data for a crystal of Cm(IO{sub 3}){sub 3} over a period of time revealed a gradual expansion of the unit cell from self-irradiation. After 71 days, the new parameters were: a=7.2132(7)A, b=8.5310(8)A, c=13.505(1)A, {beta}=100.021(2){sup o}, V=818.3(2)
- OSTI ID:
- 20658218
- Journal Information:
- Journal of Solid State Chemistry, Vol. 177, Issue 12; Other Information: DOI: 10.1016/j.jssc.2004.09.015; PII: S0022-4596(04)00512-2; Copyright (c) 2004 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
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