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The structure of Yb3+ aquo ion and chloro complexes in aqueous solutions at up to 500 ??C and 270 MPa

Journal of Physical Chemistry A

By:
, , , ,
DOI: 10.1021/jp020140q

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Abstract

We report here on X-ray absorption fine structure (XAFS) measurements used to determine the structure of the Yb3+ ion in aqueous solutions over a range of temperatures from 25 to 500 ??C and pressures up to 270 MPa. Fluorescence Yb L3-edge spectra were collected separately from nitrate (0.006m Yb/0.16m HNO3) and chloride (0.006 m YbCl3/0.017 m HCl) aqueous solutions within a hydrothermal diamond anvil cell. The Yb-O distance of the Yb3+ aquo ion in the nitrate solution exhibits a uniform reduction at a rate of 0.02 A??/100 ??C, whereas the number of oxygens decreases from 8.3 ?? 0.6 to 4.8 ?? 0.7, in going from 25 to 500 ??C. No evidence for nitrate complexes was found from measurements made on this solution. The Yb3+ is found to persist as an aquo ion up to 150 ??C in the chloride aqueous solution. In the 300-500 ??C range, chloro complexes are found to occur in the solution, most likely of the type Yb(H2O)??-nCln+3-n (?? ??? 7). The Yb-Cl distance of the chloro ytterbium(III) complexes is found to decrease uniformly at a rate of about 0.02 A??/100 ??C, whereas the number of chlorines increases from 0.5 ?? 0.3 to 1.8 ?? 0.2 in the 300-500 ??C temperature range. Conversely, the Yb-O distance undergoes a lower uniform reduction at a rate of 0.007 A??/100 ??C, whereas the number of oxygens decreases from 8.3 ?? 0.5 to 5.1 ?? 0.3 in going from 25 to 500 ??C in the same solution.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
The structure of Yb3+ aquo ion and chloro complexes in aqueous solutions at up to 500 ??C and 270 MPa
Series title:
Journal of Physical Chemistry A
DOI:
10.1021/jp020140q
Volume
106
Issue:
28
Year Published:
2002
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Physical Chemistry A
First page:
6591
Last page:
6599
Number of Pages:
9