Synthesis and characterization of environmentally benign calcium-doped Pr{sub 2}Mo{sub 2}O{sub 9} pigments: Applications in coloring of plastics

A new class of environmentally benign rare earth pigments of general formula Pr{sub 2-x}Ca{sub x}Mo{sub 2}O{sub 9-{delta}} (x ranges from 0 to 1.0) displaying colors ranging from green to yellow were synthesized by traditional solid-state route, as alternatives to lead, cadmium and chromium colorants. The products were characterized by X-ray powder diffraction, UV-vis spectroscopy and CIE-L*a*b* 1976 color scales. The coloring mechanism is based on the strong absorptions of the pigments in the blue and red regions due to electronic transitions between 4f{sup 2}{yields}4f{sup 1}5d{sup 1} states of Pr{sup 3+}. The designed pigments consist of non-toxic elements and further found to be thermally and chemically stable. The yellow-green pigments were found to be interesting alternatives to existing toxic pigments for coloration of plastics. - Graphical abstract: A new class of environmentally benign rare earth pigments of general formula Pr{sub 2-x}Ca{sub x}Mo{sub 2}O{sub 9-{delta}} (x ranges from 0 to 1.0) displaying colors ranging from green to yellow were synthesized by traditional solid-state route, as alternatives to lead, cadmium and chromium colorants. The yellow-green pigments were found to be interesting alternatives to existing toxic pigments for coloration of plastics. Display Omitted.