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An Unusual Valence State: Trivalent Europium in Intermetallic Eu2 Ir3 Al9.

Frank StegemannTheresa BlockSteffen KlennerOliver Janka
Published in: Chemistry (Weinheim an der Bergstrasse, Germany) (2019)
Eu2 Ir3 Al9 , synthesized from the elements in tantalum tubes, is one of the rare examples for trivalent europium in the field of intermetallic compounds. The compound crystallizes in the Y2 Co3 Ga9 -type structure (space group Cmcm), with lattice parameters fitting in between the isostructural samarium and gadolinium compounds. In the crystal structure, the Eu atoms form Al3 -triangle-centered honeycomb layers and exhibit a coordination number of 17 in the shape of a fivefold-capped hexagonal prism (Eu@Ir6 Al6 +Al5 ). Magnetic measurements indicate an overall low susceptibility, in line with van Vleck paramagnetism caused by the Eu3+ cations. Fits of the susceptibility yield a coupling constant of λ=290(10) K and an effective magnetic moment of μeff =4.56(1) μB , in line with a slight hybridization of the 7 F0 and 7 F1 state. 151 Eu Mössbauer spectroscopic investigations unambiguously prove the presence of solely Eu3+ in the bulk material.
Keyphrases
  • crystal structure
  • magnetic resonance imaging
  • magnetic resonance
  • molecularly imprinted
  • mass spectrometry
  • molecular dynamics simulations