Effect of Mn doping into the octahedral WO₆ unit on the yellow-orange coloration of triclinic LiCeW₂O₈

Abstract

A novel environmentally friendly inorganic yellow-orange pigment, LiCeW_2−xMn_xO_8−δ (0 ≤ x ≤ 0.07), was synthesized and its optical and color properties were investigated. By partially substituting Mn, a promising source of orange-red coloration, into the octahedrally coordinated W site of the LiCeW₂O₈ host lattice, the absorption intensity of d–d transitions associated with W and Mn in octahedral coordination was modulated, thereby enabling control over light reflection in the visible spectrum. X-ray photoelectron spectroscopy and Rietveld refinement suggested that the electronic states of the constituent elements may have influenced the d–d transition absorption intensities of W^(6−δ)+ and Mn^(4−δ)+ species, thereby altering the overall light absorption behavior. As a result, the reflectance of LiCeW_1.97Mn_0.03O_8−δ was selectively enhanced in the red region, yielding the most vivid and bright orange pigment.