Structural investigation of platinum solubility in silicate glasses
The coordination environment of 20--200 ppm Pt in yellowish glasses from the CaO-Al{sub 2}O{sub 3}-SiO{sub 2} (CAS) ternary was studied using X-ray absorption fine structure spectroscopy at the Pt-L{sub III} edge. Analysis of the Pt-L{sub 111} edge region suggests that Pt in these glasses is mainly tetravalent and sixfold-coordinated by O (with a mean Pt-O distance of 2.08 {+-} 0.02 {angstrom}). No evidence for Pt{sup 2+} or Pt{sup 6+} was found in any of the glasses studied, suggesting that one can not derive valence information easily from solubility data. No second-neighbor contribution was observed around Pt{sup 4+}O{sub 6} polyhedra. However, bond-valence modeling suggest that these polyhedra are likely to bond mostly to {sup [VI]}Ca{sup 2+}, which should promote high positional disorder of second-neighbor cations around Pt. This particular bonding arrangement may explain the relatively high solubility of Pt in these relatively depolymerized melts, as CaPtO{sub 3}-type units.
- Research Organization:
- Univ. de Marne-la-Vallee (FR)
- OSTI ID:
- 20000952
- Journal Information:
- American Mineralogist, Vol. 84, Issue 10; Other Information: PBD: Oct 1999; ISSN 0003-004X
- Country of Publication:
- United States
- Language:
- English
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