Syntheses, structures, physical properties, and electronic properties of some AMUQ3 compounds (A = Alkali metal, M = Cu or Ag, Q = S or Se)

Jiyong Yao, Daniel M. Wells, George H. Chan, Hui Yi Zeng, Donald E Ellis, Richard P Van Duyne, James A Ibers

Research output: Contribution to journalArticle

22 Scopus citations

Abstract

The seven new isostructural quaternary uranium chalcogenides KCuUS 3, RbCuUS3, RbAgUS3, CsCuUS3, CsAgUS3, RbAgUSe3, and CsAgUSe3 were prepared from solid-state reactions. These isostructural materials crystallize in the layered KZrCuS3 structure type in the orthorhombic space group Cmcm. The structure is composed of UQ6 octahedra and MQ4 tetrahedra that share edges to form 2[UMQ 3 -] layers. These layers stack perpendicular to [010] and are separated by layers of face- and edge-sharing AQ8 bicapped trigonal prisms. There are no Q-Q bonds in the structure, so the formal oxidation states of A/U/M/Q may be assigned as 1+/4+/1+/2-, respectively. CsCuUS3 shows semiconducting behavior with thermal activation energy Ea = 0.14 eV and σ298 = 0.3 S/cm. From single-crystal absorption measurements in the near IR range, the optical band gaps of these compounds are smaller than 0.73 eV. The more diffuse 5f electrons play a much more dominant role in the optical properties of the AMUQ3 compounds than do the 4f electrons in the AMLnQ3 compounds (Ln = rare earth). Periodic DFT spin band-structure calculations on CsCuUS3 and CsAgUS3 establish two energetically similar antiferromagnetic spin structures and show magnetic interactions within and between the layers of the structure. Density-of-states analysis shows M-Q orbital overlap in the valence band and U-Q orbital overlap in the conduction band.

Original languageEnglish (US)
Pages (from-to)6873-6879
Number of pages7
JournalInorganic Chemistry
Volume47
Issue number15
DOIs
StatePublished - Aug 4 2008

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

Fingerprint Dive into the research topics of 'Syntheses, structures, physical properties, and electronic properties of some AMUQ<sub>3</sub> compounds (A = Alkali metal, M = Cu or Ag, Q = S or Se)'. Together they form a unique fingerprint.

  • Cite this