Oxidation‐reduction Equilibria in Glass Between Iron and Selenium in Several Furnace Atmospheres*

A bstract This study has been limited to the reactions between iron and selenium in soda‐lime and potash‐soda‐lime glasses melted in atmospheres of air, nitrogen, and carbon monoxide. Glasses containing selenium and iron, together and singly, were melted in the several atmospheres. and their spectral absorption curves between 350 and 1000 mμ were obtained. An analysis of these curves shows that under neutral or slightly oxidizing conditions selenites react with ferrous iron as follows: image This reaction leads to an increase in red and brown and a decrease in blue colors. The decolorizing action of selenium may be explained by this reaction because the colorless selenite ion oxidizes the more colored ferrous ion to the less colored ferric ion, arid the increase in the red elemental selenium color physically compensates as a complimentary color for the remaining unoxidized ferrous ion. The results show that it is not necessary to postulate the formation of ferrous selenium to explain the color changes. The results also show that under reducing conditions the principal reaction is image