| Abstract
| - The Ce−Si−S system has been explored in search of new, yellow non-toxic pigments. In relation with a CeIII-4f1 → CeIII-5d1 electronic transition, Ce2SiS5, Ce4Si3S12, and Ce6Si4S17 present strong absorption bands at 2.35(1)eV, 2.38(1)eV, and 2.56(1)eV, respectively. From band structure calculations, it is shown that the difference in the position of the absorption onset can be attributed to Ce atoms of net atomic charge lower than that in the first two compounds.
- The Ce−S−Si system has been explored in search of new, yellow nontoxic pigments. Weprepared a new Ce−S−Si phase (Ce6Si4S17), determined the crystal structures of Ce2SiS5,Ce4Si3S12, and Ce6Si4S17, and measured the chromatic properties of these Ce−S−Si phases.The differences in the yellow hue of these compounds were probed by analyzing their Ce3+ion environments and calculating their electronic band structures. Ce6Si4S17 is distinguishedfrom Ce2SiS5 and Ce4Si3S12 in terms of the Ce3+ structural environment and the Ce3+ 4f1→5d0transition gap. This gap is wider for Ce6Si4S17 than for Ce2SiS5 and Ce4Si3S12 (i.e., 2.51 vs.∼2.36 eV), and Ce6Si4S17 exhibits room-temperature luminescence whereas Ce2SiS5 and Ce4Si3S12 do not. Ce4Si3S12 and Ce6Si4S17 possess chromatic properties similar to those foundfor industrial pigments such as PbCrO4, BiVO4, and CdS, and show thermal and chemicalstabilities.
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