The valence state of uranium in K6Cu12U 2S15

H. Schilder, M. Speldrich, H. Lueken, A. C. Sutorik, M. G. Kanatzidis

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


The paramagnetic behaviour of K6Cu12U 2S15 has been analysed, regarding copper as diamagnetic (Cu+), sulfur as mixed-valent S2-/S- with magnetically silent delocalized S- holes in the valence band, and the actinide as either U5+[5f1] or U4+[5f 2] in trigonally distorted octahedral surrounding (pseudosymmetry 3̄m) of sulfur. Fitting procedures have been carried out, accounting for spin-orbit coupling, ligand-field potential (parameters Bk q), interelectronic repulsion (for U4+[5f2]), cooperative magnetic effects (molecular field parameter λ), and applied magnetic field. Keeping the ratios B43/B4 0, B63/B60, B 66/B60 on their point charge electrostatic values with respect to the sulfur ligands, the three axial parameters Bk0 (k=2,4,6) and λ were refined. Agreement between measured and calculated susceptibility data was obtained for U5+ with Bk0 values expected for octahedral surrounding and λ<0 speaking for antiferromagnetic interactions. The U4+ model does yield a fit of comparable quality, but gives B k0 values that are unreasonable with respect to sign and magnitude. To conclude, on the basis of the magnetic properties the title compound is a 5f1 system corresponding to the elements formal charges (K+)6(Cu+)12(U5+) 2(S2-)13(S-)2.

Original languageEnglish
Pages (from-to)249-252
Number of pages4
JournalJournal of Alloys and Compounds
Issue number1-2
Publication statusPublished - Jul 14 2004


  • Actinide
  • KCuUS
  • Magnetic properties
  • Mixed-valent S/S

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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