Thermodynamic properties and phase transitions of Tutton salt (NH4)2Co(SO4)2·6H2O crystals

Theoretical studies of the g factors and local structures of the Ni3+ centers in Na2Zn(SO4)2·4H2O and K2Zn(SO4)2·6H2O crystals

“…Different from the ordinary 3d 7 (e.g., Co 2+ and Fe + ) ions of weak or intermediate crystal-field case with high spin (S = 3/2), Ni 3+ (3d 7 ) in DPPH, and PHZS crystals belongs to strong crystal-field case with low spin (S = 1/2) and exhibits different physical mechanisms such as strong covalency and Jahn-Teller effect. On the one hand, the microscopic mechanisms of the g factors and local structural information for Ni 3+ dopants in DPPH and PHZS crystals may help researchers further understand the properties of Tutton salts containing TM impurities.…”

“…[4,5] In addition, the phase transitions, proton conductivity, optical, magnetic, thermodynamic, and structural properties of Tutton compounds doped with transition-metal (TM) ions have been the important subject of intense research in recent years. [6][7][8][9][10] Usually, TM impurities play a crucial role in the above properties, which may be sensitively correlated to the local structures and electronic states of the doped TM ions in the host crystals. As is known, electron paramagnetic resonance (EPR) technique can provide useful information about the local structures and the dynamics for these TM impurities in the host lattices and enable to identify the site symmetries and electric fields around the dopants in the hosts.…”

“…Thus, investigates on the g factors and local lattice deformations for the Ni 3+ centers in DPPH and PHZS crystals are necessary and very meaningful. In this work, the g factors and local structures of DPPH:Ni 3+ and PHZS:Ni 3+ are theoretically studied from the perturbation formulas of the g factors for orthorhombically compressed octahedral 3d 7 clusters. In the calculations, the contributions from the ligand orbital and spin-orbit coupling interactions are considered due to the covalent property of the studied systems, and the local lattice deformations due to the Jahn-Teller effect are also quantitatively involved.…”

Investigation of the EPR parameters of the rhombic Cu2+center in (NH4)2Mg(SO4)2·6H2O single crystal

“…The cubic field parameters D q , tetragonal field parameters D s and D t (in cm −1 ), N γ and λ γ (and λ s ), spin-orbit coupling coefficients ζ and ζ (in cm −1 ), orbital reduction factors k and k for MPPH: Cu 2+ crystal. a Calculations based on the simple second-order perturbation formulas and various adjustable molecular orbital coefficients in the previous work ( Equation (1) and fitting the calculated EPR parameters to the experimental data, we have:…”

“…Tutton salts of M I 2 M II (SO 4 ) 2 ·6H 2 O (here, M II denotes various divalent metal ions and M I = NH 4 , K, Rb, Cs) exhibit interesting phase transitions (1), dielectric (2), thermodynamic (1) and structure properties (1). Especially, the optical and magnetic properties of the Tutton salts have been extensively studied for these materials doped with some transition-metal (e.g.…”