Synthesis of new environment-friendly yellow pigments

New inorganic pigments based on amorphous cerium tungstate, Ce1−xMxW2O8 (M = Zr or Ti, 0 ≤ x ≤ 0.6), were synthesized and their color properties were characterized from the viewpoint of possible ecological inorganic pigments. The Ce1−xMxW2O8 materials absorb the visible and the ultraviolet light under 500 nm efficiently, which is originated in the O2p–Ce4f and the O2p–W5d double charge transfer transitions, and, as a result, the pigments can show a brilliant yellow color. The optical absorption edge wavelength of these pigments depends on the Zr or Ti content, and the effective yellow hue was observed at x = 0.2 for both pigments. The color properties of the present pigments suggest that they have a potential to be applied as a satisfactory pigment for paints. Furthermore, these pigments can be prepared by a simple co-precipitation method. They are inert and safe and do not produce side effects in the human body because they are composed of non-toxic and safe elements.