Observation and interpretation of 157.5 T internal magnetic field in Fe[C(SiMe3)3]2 coordination compound

Erno Kuzmann, Roland Szalay, Attila Vértes, Zoltán Homonnay, Imre Pápai, Peter De Châtel, Zoltán Klencsár, László Szepes

Research output: Contribution to journalArticle

8 Citations (Scopus)


The compound Fe[C(SiMe3)3]2 has been prepared and investigated by the means of powder X-ray diffractometry and 57Fe Mössbauer spectroscopy. The compound's unique geometry, in which iron is linearly coordinated by the two C(SiMe3)3 ligands, results in a unusual electronic structure of iron, which is visualized as an extreme high hyperfine magnetic field of 157.5(8) T as sensed by the 57Fe nucleus at T = 20 K. In order to obtain information on the electronic structure of iron and on the bonds to the ligands, DFT (density functional theory) calculations were carried out on Fe[C(SiMe3) 3]2. The high-spin state of iron was found to be energetically favored: an Fe(II) electron configuration of 3d5.83 4s0.72 is predicted, where the 4s electron density is only slightly polarized, and most of the unpaired electrons have 3d character. By assuming a linear crystal field, and associated 3d level scheme as a starting point, it is suggested that the extreme high hyperfine magnetic field, observed along with an apparently negative quadrupole splitting, is perpendicular to the C-Fe(II)-C bond axis, and can be decomposed mainly into contact (B c ≈ 44 T), dipolar (B d ≈ 14 T), and orbital (B L ≈ 99 T) hyperfine magnetic field contributions.

Original languageEnglish
Pages (from-to)453-460
Number of pages8
JournalStructural Chemistry
Issue number3
Publication statusPublished - Jun 1 2009


  • Calculation
  • DFT
  • Extreme high hyperfine field
  • Fe Mössbauer spectroscopy
  • Fe coordination compound
  • Linear Fe compound

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

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