Syntheses, crystal structures, and physical properties of La 5Cu6O4S7 and La5Cu 6.33O4S7

George H. Chan, Ming Ling Liu, Li Dong Chen, Fu Qiang Huang, Daniel E. Bugaris, Daniel M. Wells, John R. Ireland, Mark C. Hersam, Richard P. Van Duyne, James A. Ibers

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14 Citations (Scopus)


Single crystal and bulk powder samples of the quaternary lanthanum copper oxysulfides La5Cu6.33O4S7 and La5Cu6O4S7 have been prepared by means of high-temperature sealed-tube reactions and spark plasma sintering, respectively. In the structure of La5Cu6.33O 4S7, Cu atoms tie together the fluorite-like 2[La5O4S5+] and antifluorite-like 2[Cu6S 65-] layers of La5Cu6O 4S7. The optical band gap, Eg, of 2.0 eV was deduced from both diffuse reflectance spectra on a bulk sample of La 5Cu6O4S7 and for the (010) crystal face of a La5Cu6.33O4S7 single crystal. Transport measurements at 298 K on a bulk sample of La 5Cu6O4S7 indicated p-type metallic electrical conduction with σelectrical = 2.18 S cm -1, whereas measurements on a La5Cu6.33O 4S7 single crystal led to σelectrical = 4.5 10-3 S cm-1 along [100] and to semiconducting behavior. In going from La5Cu6O4S7 to La5Cu6.33O4S7, the disruption of the 2[Cu6S65-] layer and the decrease in the overall Cu2+ (3d9) concentration lead to a significant decrease in the electrical conductivity.

Original languageEnglish
Pages (from-to)4368-4374
Number of pages7
JournalInorganic Chemistry
Issue number10
Publication statusPublished - May 19 2008

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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