title: Li11Nd18Fe4O(39-δ) revisited.
abstract: The structure proposed for Li(11)Nd(18)Fe(4)O(39-δ) (Chen et al. Inorg. Chem. 2012, 51, 8073) on the basis of diffraction and Mössbauer spectral data is compared to that determined previously for Nd(18)Li(8)Fe(5)O(39) (Dutton et al. Inorg. Chem.200847, 11212) using the same techniques. The Mössbauer spectrum reported by Chen et al. has been reinterpreted. The newly refined spectral parameters differ significantly from the published values but are similar to those reported for Nd(18)Li(8)Fe(5)O(39). The relative areas of the three components indicate that iron cations occupy the 2a, 8e, and 16i sites in space group Pm3n, in disagreement with the model determined from neutron diffraction by Chen et al. in which only the 2a and 8e sites are so occupied. The relationship between Li(11)Nd(18)Fe(4)O(39-δ) and Nd(18)Li(8)Fe(5)O(39) is discussed, and it is proposed that the sample prepared by Dutton et al. is a kinetic product whereas the sample prepared by Chen et al. is the thermodynamically preferred product.
authors.affiliation: Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK. peter.battle@chem.ox.ac.uk
authors.forename: Peter D
authors.initials: PD
authors.lastname: Battle
authors.forename: Sian E
authors.initials: SE
authors.lastname: Dutton
authors.forename: Fernande
authors.initials: F
authors.lastname: Grandjean
authors.forename: Gary J
authors.initials: GJ
authors.lastname: Long
authors.forename: Katsuyoshi
authors.initials: K
authors.lastname: Oh-ishi