Realising blue colour in cobalt substituted silicates: Synthesis, structure and optical studies

In an attempt to develop new blue coloured inorganic oxides, we have undertaken the cobalt substitution in Zn2SiO4 and Ba2ZnSi2O7. In both the compounds, Zn occupies a tetrahedral coordination. Our studies indicate formation of single-phase materials only up to x = 1.0 in Zn2-xCoxSiO4 and full replacement of Zn in Ba2Zn1-xCoxSi2O7. The obtained compounds exhibit sky blue to intense blue colour, which appears to be stable in boiling water. The cobalt based blue compounds may be useful as new inorganic blue pigments