New red-shade ceramic pigments based on Y2Sn2-xCrxO7-δ pyrochlore solid solutions

New high-stability red-shade ceramic pigments based on pyrochlore solid solutions Y2Sn2-xCrxO7-delta (x = 0-1, 0 < delta = 0-(1)/(2)x) were developed employing conventional solid-state reaction synthesis. The relationship between their optical properties and microstructure was analyzed by X-ray diffractometry and ultraviolet-visible-light spectroscopy. Decomposition of the structure with formation of the perovskite YCrO3 observed for chromium substitutions x 2: 5 was attributed mainly to high concentration of defects. The structural and optical parameters of the materials were found to correlate with the concentration of a species with higher oxidation state than Cr(III), such as Cr(IV) or Cr(V).