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Syntheses, Structures, Physical Properties, and Theoretical Studies of CeMxOS (M = Cu, Ag; x ≈ 0.8) and CeAgOS
| Content Provider | Semantic Scholar |
|---|---|
| Author | Chan, George H. Deng, Bin Bertoni, Mariana I. Ireland, John R. Hersam, Mark C. Mason, Thomas O. Duyne, Richard P. Van Ibers, James A. |
| Copyright Year | 2006 |
| Abstract | Black single crystals of the two nonstoichiometric cerium coinage-metal oxysulfide compounds CeCuxOS and CeAg x OS (x ≈ 0.8) have been prepared by the reactions of Ce 2 S 3 and CuO or Ag 2 O at 1223 or 1173 K, respectively. A black powder sample of CeAgOS has been prepared by the stoichiometric reaction of Ce 2 S 3 , CeO 2 , Ag 2 S, and Ag at 1073 K. These isostructural materials crystallize in the ZrSiCuAs structure type with two formula units in the tetragonal space group P4/nmm. Refined crystal structure results and chemical analyses provide evidence that the previously known anomalously small unit-cell volume of LnCuOS for Ln = Ce (Ln = rare-earth metal) is the result of Cu vacancies and the concomitant presence of both Ce 3+ and Ce 4+ . Both CeCu 0.8 OS and CeAgOS are paramagnetic with μ eff values of 2.13(6) and 2.10(1) μ B , respectively. CeCu 0.8 OS is a p-type semiconductor with a thermal activation energy E a = 0.22 eV, σ electrical = 9.8(1) 10 -3 S/cm at 298 K, and an optical band gap Eg < 0.73 eV. CeAgOS has conductivity σ conductivity = 0.16(4) S/cm and an optical band gap Eg = 0.71 eV at 298 K. Theoretical calculations with an on-site Coulomb repulsion parameter indicate that the Ce 4f states are fully spin-polarized and are not localized in CeCuOS, CeCu 0.75 OS, or CeAgOS. Calculated band gaps for CeCu 0.75 OS and CeAgOS are 0.6 and 0.8 eV, respectively. |
| Starting Page | 8264 |
| Ending Page | 8272 |
| Page Count | 9 |
| File Format | PDF HTM / HTML |
| DOI | 10.1021/ic061041k |
| Volume Number | 45 |
| Alternate Webpage(s) | http://sites.northwestern.edu/vanduyne/files/2012/10/2006_Chan_2.pdf |
| Alternate Webpage(s) | https://doi.org/10.1021/ic061041k |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
