Investigation of the Bonding of Iron-Group Ions in Fluoride Crystals. II

Abstract

This paper describes an ESR investigation of the bonding of iron-group ions with the configurations d6(Fe2+) and d7(Fe+, Co2+, Ni3+) on cubic lattice sites in the crystals LiF, NaF, and KMgF3. To aid the analysis of the bonding of d7 ions, the optical absorption spectrum of Co2+ was measured in LiF and KMgF3. A discussion is given of the effects of lattice dimensions and the charge state of the impurity ion on the bonding parameters.

Comment on “Theoretical investigations of the hyperfine interactions for Co2+ in the fluoroperovskites” [Chem. Phys. 348 (2008) 199]

“…Apart from this trouble, the analysis made by Wu et al is unable to explain the actual origin of a relevant issue emerging in the comparison between the experimental g, A and 10Dq values of KMgF 3 :Co 2+ and BaLiF 3 :Co 2+ [5][6][7][8]. As the lattice parameter, a, of LiBaF 3 and KMgF 3 [9,10] are nearly identical (Table 1) it could be expected that the electronic properties due to the CoF 4À 6 complex in such lattices would be practically the same.…”

“…Available experimental values of g, A and 10Dq measured for Co 2+ -doped BaLiF 3 , KMgF 3 [5][6][7][8] and also KZnF 3 [11] Table 1. The calculation procedure is the same previously employed for deriving the equilibrium metal-ligand distance for Ni 2+ [12] and Mn 2+ [4] impurities in BaLiF 3 and KMgF 3 .…”

“…g and A values for Co 2+ -doped KMgF 3 , BaLiF 3 and KZnF 3 come from Refs. [5,6,10], respectively, while 10Dq values come from Ref. [7].…”

Investigations on the EPR Parameters of KMgF3:Cr+

“…A D and A σ −A π stand for the anisotropic contributions from the dipoledipole interaction between the electron of the central ion and ligand nucleus and that from the ligand 2p orbital, respectively. The isotropic part can be further expressed as follows [20]: [21] for the ligand F − . The electron spin is S = 5/2 of the ground state 6 A 1g for Cr + in KMgF 3 .…”

Optical and magnetic properties of transition-metal ions in tetrahedral and octahedral compounds

“…In order to compare the general features, for example the crystal-field strength and covalence effect, of TMIs in tetrahedron with those in octahedron [30][31][32][33][34][35][36], a sequence of cubic crystal-field strength Dq and Racah parameter B for tetrahedral and octahedral crystals are given in Table 7.…”