| Abstract
| - An investigation made into the variation of oxide(−II) electronic polarizability, αoxide(-II), for glasses coveringa wide range of composition shows that there is an almost linear relationship between αoxide(-II) and glassbasicity (expressed as optical basicity, Λ). However, systematic deviations pinpoint the role of coordinationnumber on the polarizing power of cations such as Al3+, Ge4+, and Mg2+. Data for glasses containing thesecations indicate that the oxide(−II) atoms of the glass undergo the same degree of polarization regardless ofwhether these cations exercise a coordination number of four or six. The results of previous studies on cationiccharge trends for Fe3+ in glass are now explicable on this basis. Furthermore, it is shown that when the effectof coordination number is taken into account in the calculation of Λ for crystalline metal oxides (such asAl2O3 or GeO2) and also metal silicates and aluminosilicates, there is good agreement with the αoxide(-II)/Λtrend already established for glasses. The optical basicity model is currently applied to technical problemsconcerned with metallurgical slag performance and also glass melts, and the present findings are expected tohave important implications for these materials.
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