Influence of glass basicity on redox interactions of iron-manganese-copper ion pairs in soda-lime-silica glass

Abstract

The redox interactions of iron, manganese, and copper ion pairs including absorption characteristics in a multicomponent soda-lime-silica glass, were investigated. Glasses containing 11-19 mol % Na 2 O were melted under an air atmosphere in an electric furnace at 1450 ° C for 8 h. The results of chemical analysis indicated that the redox pairs of Fe 2+ /Fe 3+ , Mn 2+ /Mn 3+ , and Cu + /Cu 2+ shift to more oxidized states as a function of increasing glass basicity. The redox interactions of individual pairs, e.g., Fe 2+ /Fe 3+ -Mn 2+ /Mn 3+ , Fe 2+ /Fe 3+ -Cu + /Cu 2+ , and Mn 2+ /Mn 3+ -Cu + /Cu 2+ , were not strong but changed with glass basicity. For the three redox pairs, Fe 2+ /Fe 3+ -Mn 2+ /Mn 3+ -Cu + /Cu 2+ , both Mn 3+ and Cu 2+ ions simultaneously and proportionally oxidized Fe 2+ to Fe 3+ and did not affect one another. The reaction constants log Q 2 of Fe 2+ /Fe 3+ -Mn 2+ /Mn 3+ and Mn 2+ /Mn 3+ -Cu + /Cu 2+ redox pairs decreased while the Fe 2+ /Fe 3+ -Cu + /Cu 2+ and three redox pairs systems changed markedly with increasing the glass basicity. The oxidizing and reducing powers of each ion changed only slightly in the present of one another, and the absorption spectra of all the single polyvalent elements confirmed to the Lambert-Beer law. The spectra depended directly on the concentrations of each absorbing ion. While the spectra of glass doped with more than one element confirmed the direction of the equilibrium shift, they were used only to predict the degree of interaction. These investigations gave consistent results.

Spectroscopic Investigation of the Coloration and Fabrication Conditions of Medieval Blue Glasses

“…Moreover, Mn must be considered as it was used to oxidize iron. Therefore complex redox interactions are expected between these glass components …”

“…Therefore complex redox interactions are expected between these glass components. 16 Optical and X-ray absorption spectroscopies enable to probe TM speciation: XANES is an element-specific technique while optical absorption spectroscopy probes only coloring species. XANES is widely used to determine the speciation and the redox state of TM in glass 17 including ancient glasses.…”

The Influence of Cu2+ and Mn2+ Ions on the Structure and Crystallization of Diopside–Calcium Pyrophosphate Bioglasses

“…However, Table reveals ‎an opposite effect and a lower CTE value was measured for Mn‐5 . The heat treatment ‎is likely to cause changes in oxidation state (from Mn 2+ to Mn +3 , or even Mn 4+ ), a ‎commonly observed phenomenon in glasses doped with some transition elements . ‎Accordingly, Mn plays a complex role on the structure and properties of glasses .…”

“…The heat treatment is likely to cause changes in oxidation state (from Mn 2+ to Mn +3 , or even Mn 4+ ), a commonly observed phenomenon in glasses doped with some transition elements. [34][35][36] Accordingly, Mn plays a complex role on the structure and properties of glasses. 37 The apparent chemical shift, from À83.5 ppm (CaP-10) to À79.5 ppm (Mn-5) in Fig.…”

Role of manganese on the structure, crystallization and sintering of non-stoichiometric lithium disilicate glasses

“…Whenever, added to silicate glass systems, Mn tends to exist either in 3+ or 2+ oxidation state; higher oxidation states such as 4+ and 7+ are possible but very unlikely. 35,45 This redox equilibrium is common in glass systems doped with transition elements, 6 and several studies 6,46,47 proved that the redox ratio depends on glass optical basicity (L) when other parameters are maintained constant. In the present study, the calculated optical basicity (L cal ) ( Table 2) for the experimental glasses revealed only slight increments with the composition.…”