Electronic absorption spectroscopy and colour of chromium-doped solids

Twenty-one chromium-containing compounds and solid solutions belonging to ten structural types were obtained by either solid-state reactions or the Pechini method and studied from the point of view of the relationship between structure, composition and colour. Formation of single-phase products was assured by heating on several high-temperature stages and monitoring phase transformations by X-ray diffraction. Electronic absorption spectra and colour coordinates of the samples were obtained and analysed paying special attention to the dependence of the colour on the structural characteristics and the presence of chromium in oxidation states other than Cr(III).