High- versus Low-Spin Ni²⁺ in Elongated Octahedral Environments: Sr₂NiO₂Cu₂Se₂, Sr₂NiO₂Cu₂S₂, and Sr₂NiO₂Cu₂(Se_1-x S _x )₂.

ABSTRACT: Sr₂NiO₂Cu₂Se₂, comprising alternating [Sr₂NiO₂]²⁺ and [Cu₂Se₂]^2- layers, is reported. Powder neutron diffraction shows that the Ni²⁺ ions, which are in a highly elongated NiO₄Se₂ environment with D_4h symmetry, adopt a high-spin configuration and carry localized magnetic moments which order antiferromagnetically below ∼160 K in a √2a × √2a × 2c expansion of the nuclear cell with an ordered moment of 1.31(2) μ_B per Ni²⁺ ion. The adoption of the high-spin configuration for this d ⁸ cation in a pseudo-square-planar ligand field is supported by consideration of the experimenta

SUBMITTER: Smyth RD 

PROVIDER: S-EPMC9648177 | biostudies-literature | 2022 Nov

REPOSITORIES: biostudies-literature