Molar extinction coefficients of the cupric ion in silicate glasses

Singh, Shailendra; Kumar, Alok

doi:10.1007/bf00349674

Cited by 32 publications

(22 citation statements)

References 6 publications

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“…This means that the coordination of these ions, octahedral sites for Mn 3+ , Cu 2+ and Cr 3+ ions and tetrahedral sites for Ni 2+ and Co 2+ ions, do not change with change in the range of basicity between 0⋅558 and 0⋅587 as the Na 2 O content increased from 10-16 mol%. Moreover, the ligand field strength (Dq) for these ions may be presented at high ligand field and also high stabilization energy, and/or is insensitive to given condition in this work (Singh and Kumar 1995;Dawy and Salama 2001).…”

Section: Optical Absorption and Colourationmentioning

confidence: 95%

Redox ratio and optical absorption of polyvalent ions in industrial glasses

et al. 2007

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The changes in glass structure and redox ratio, R (reduced ion to oxidized ion) of Mn 2+ -Mn 3+ , Cu + -Cu 2+ , Cr 3+ -Cr 6+ , Ni 2+ -Ni 3+ and Co 2+ -Co 3+ couples and optical absorption due to Mn 3+ , Cu 2+ , Cr 3+ , Ni 2+ and Co 2+ ions in industrial soda-lime-silica glass were investigated as a function of Na 2 O concentration in the range 11-19 mol%. With increasing Na 2 O concentration in the experimental glasses, the basicity, expressed as calculated basicity, Λ cal , increased. 29 Si NMR and X-ray diffraction were used to investigate the structural change in glasses. The NMR spectra showed high non-bridging oxygens (NBOs) when the basicity of glass was increased. The results were interpreted to be due to the tetrahedral networks; Q 4 species were depolymerized by replacing the bridging oxygens (BOs) with NBOs to Q 3 species. These results confirmed the shift of broadening peaks of XRD patterns. The redox reactions of the Mn 2+ -Mn 3+ , Cu + -Cu 2+ and Cr 3+ -Cr 6+ couples shifted more toward their oxidized ions due to the oxygen partial pressure, p(O 2 ), during melting and the oxide ion activity, a O2-, increased with increasing glass basicity. These changes caused the redox ratio of these ion couples to decrease. The Ni 2+ -Ni 3+ and Co 2+ -Co 3+ couples were assumed to be present only in the Ni 2+ and Co 2+ ions in these glasses, respectively. The optical absorption bands due to Mn 3+ , Cu 2+ , Cr 3+ , Ni 2+ and Co 2+ ions were also investigated. Their spectra occurred at constant wavelengths with different optical densities or intensities as a function of glass basicity. The increase in the intensities of the absorption bands of these absorbing ions, except for Cr 3+ ion, at the maximum wavelength, depends not only on the ion concentration but also on the increase of polarizability of oxide (-II) species, α oxide(-II) , surrounding the ions. This value affected directly the extinction coefficients of the ions, ε ion . The increase of ε ion caused the colour of glasses appearing in high intensity. In the case of Cr 3+ ion, the results were reversed such that the lower the concentration, the higher the intensities of colour.

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Section: Optical Absorption and Colourationmentioning

confidence: 95%

Redox ratio and optical absorption of polyvalent ions in industrial glasses

et al. 2007

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“…The amount of Tenorite at the surface of the coating produces the different aesthetical aspects observed as a function of the coating thickness. The greenish-brown color of the thinnest coating is the characteristic of copper and iron, respectively, dissolved in the glassy phase (S50) [25], and a very limited amount of copper is segregated from the phase due to the small thickness of the glaze coating. When the coating thickness increases, the copper cations migrates towards the surface due to its high mobility on melted glassy matrix [26] giving rise to a copper saturated surface.…”

Section: Resultsmentioning

confidence: 99%

Inorganic hydrophobic coatings: Surfaces mimicking the nature

Reinosa

Romero

Rubia

et al. 2013

Ceramics International

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Added value products are being developed in ceramic industry. Different optical effects as bright metallic shine or new functionalities as hydrophobicity or bactericide characteristics are the new properties searched on the tiles. In this study, we prepare glassy coatings for tiles based on copper pigment by a conventional industrial process. The obtained coatings present different aesthetical aspects, including bright metallic aspect which confers a high decorative value to the tile. Furthermore, these metallic coatings present hydrophobic properties with contact angles with water as high as 115° and also bactericide characteristics. Superficial microstructure and nanoparticles were found in the bactericide-hydrophobic samples, resembling the surface of hydrophobic leaf surfaces. This structure was formed by the crystallization of CuO nanoparticles as Tenorite due to the copper saturation of the glassy matrix at the surface of the coatings.

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“…According to the literature [15][16][17][18] in alkali-silicate glasses with Na 2 O-concentrations >20 mol%, copper is the only polyvalent element which redox equilibrium is shifted with increasing Na 2 O-concentration to the reduced species. By contrast, for soda-lime-silicate glass, Singh and Kumar [19] as well as Cable and Xiang [20] reported that the Cu + /Cu 2+ equilibrium is shifted towards the oxidized species with increasing basicity. Also from binary soda-silicate melts with Na 2 O-concentrations in the range from 25 to 40 mol%, a shift of the redox equilibrium to the oxidized state with increasing basicity was reported (see [21]).…”

Section: Introductionmentioning

confidence: 90%