Vol. 30, Issue 4, pp. 497-502 (2000)

Abstract

For oxide xerogels of the types: Na₂O-B₂O₃-SiO₂ and SiO₂-TiO₂ prepared by the sol-gel procedure a correlation between one of the absorption bands of Cr³⁺ ion (attributed to the ⁴A_2g(F) to ⁴T_2g(F) transition) and theoretical optical basicity has been found. The experimental results show that Cr³⁺ ion can play the role of basicity probe in the Lewis sense for oxide xerogels. Additionally, its band position can be a relative measure of water content in the same material.