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Theoretical studies of the g factors and local structures of the Ni 3+ centers in Na 2 Zn(SO 4 ) 2 ·4H 2 O and K 2 Zn(SO 4 ) 2 ·6H 2 O crystals
Author(s) -
Chen B.J.,
Li Y.D.,
Feng C.D.,
Zhang H.M.,
Yan C.,
Xiao W.B.
Publication year - 2020
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.5039
Subject(s) - chemistry , orthorhombic crystal system , bond length , crystallography , octahedron , crystal structure , ion , molecular geometry , molecule , organic chemistry
The local structures and the g factors g i ( i = x , y , z ) for Ni 3+ centers in Na 2 Zn(SO 4 ) 2 ·4H 2 O (DPPH) and K 2 Zn(SO 4 ) 2 ·6H 2 O (PHZS) crystals are theoretically studied by using the perturbation formulas of the g factors for a 3d 7 ion with low spin ( S = 1/2) in orthorhombically compressed octahedra. In these formulas, the contributions to g factors from both the spin‐orbit coupling interactions of the central ion and ligands are taken into account, and the required crystal‐field parameters are estimated from the superposition model and the local geometry of the systems. Based on the calculations, the Ni‐O bonds are found to suffer the axial compression δ z (or Δ z ) of about 0.111 Å (or 0.036 Å) along the z ‐axis for Ni 3+ centers in DPPH (or PHZS) crystals. Meanwhile, the Ni‐O bonds may experience additional planar bond length variation δ x (≈0.015 Å) along x‐ and y‐ axes for the orthorhombic Ni 3+ center in DPPH. The theoretical g factors agree well with the experimental data. The obtained local structural parameters for both Ni 3+ centers are discussed.