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Title: Coordination (hydration) of rare earth ions in aqueous chloride solutions from x-ray diffraction. III. SmCl/sub 3/, EuCl/sub 3/, and series behavior

Journal Article · · J. Chem. Phys.; (United States)
OSTI ID:5400728

The inner sphere water coordination of Sm/sup 3 +/ and Eu/sup 3 +/ in concentrated (3.23 m) aqueous chloride solutions was obtained from x-ray diffraction measurements at 25 /sup 0/C. The average water coordination is 8.8 for Sm/sup 3 +/ and 8.3 for Eu/sup 3 +/. The average RE/sup 3 +/--H/sub 2/O distances are 2.474 A for Sm/sup 3 +/ and 2.450 A for Eu/sup 3 +/. The average RE/sup 3 +/xxxCl/sup -/ ion pair distances occur near 4.9 A. A careful examination of the x-ray diffraction results for ten rare earth chloride solutions indicates that the inner sphere water coordination of the rare earth ions in aqueous solutions decreases from nine to eight due to the decreasing rare earth ionic radii. The ions La/sup 3 +/ through Nd/sup 3 +/ are nine coordinated, those between Nd/sup 3 +/ and Tb/sup 3 +/ are transitional between nine and eight, and those from Tb/sup 3 +/ to Lu/sup 3 +/ are eight coordinated.

Research Organization:
Ames Laboratory-USDOE, Department of Physics, and Department of Chemistry, Iowa State University, Ames, Iowa 50011
OSTI ID:
5400728
Journal Information:
J. Chem. Phys.; (United States), Vol. 73:1
Country of Publication:
United States
Language:
English