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.
MAGNETIC RESONANCE IN CHEMISTRY : MRC 2020;
58:921-928. [PMID:
32391937 DOI:
10.1002/mrc.5039]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 05/01/2020] [Accepted: 05/04/2020] [Indexed: 06/11/2023]
Abstract
The local structures and the g factors gi (i = x, y, z) for Ni3+ centers in Na2 Zn(SO4 )2 ·4H2 O (DPPH) and K2 Zn(SO4 )2 ·6H2 O (PHZS) crystals are theoretically studied by using the perturbation formulas of the g factors for a 3d7 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 δz (or Δz) of about 0.111 Å (or 0.036 Å) along the z-axis for Ni3+ centers in DPPH (or PHZS) crystals. Meanwhile, the Ni-O bonds may experience additional planar bond length variation δx (≈0.015 Å) along x- and y-axes for the orthorhombic Ni3+ center in DPPH. The theoretical g factors agree well with the experimental data. The obtained local structural parameters for both Ni3+ centers are discussed.
Collapse