Studies of the local lattice distortions for the various rhombic Ru3+ centres in AgX (X = Cl and Br). (15th October 2016)

• Record Type: Journal Article
• Authors: Hu, Xian-Fen; Wu, Shao-Yi; Li, Guo-Liang; Xu, Yong-Qiang; Ding, Chang-Chun; Zhang, Zhi-Hong
• Is Part Of: Polyhedron. Volume 117(2016)
• Page Start: 14
• Page End: 19
• Publication Date: 2016-10-15
• Subjects: Defect structures -- Electron paramagnetic resonance -- Ru3+ -- AgCl; Chemistry, Inorganic -- Periodicals; Chimie inorganique -- Périodiques; Organometaalverbindingen; Anorganische chemie; 546.05
• DOI: 10.1016/j.poly.2016.05.014
• Languages: English
• ISSNs: 0277-5387

Abstract

Graphical abstract: SHPs and local structures are theoretically studied for various rhombic Ru 3+ centres in AgX. Local lattice distortions are analysed from influences of VAg for all centres in a consistent way. Ligand orbital and spin–orbit coupling contributions are included in view of covalency of the systems. Defect structures of centres A, A ′ (a), B, B ′ (b) and X, X ′ (c) in AgX:Ru 3+ (X = Cl and Br). Abstract: The local lattice distortions of the various rhombic Ru 3+ centres ( A, A ′, B, B ′, X and X ′) in AgX (X = Cl and Br) are quantitatively investigated from the perturbation calculations of the anisotropic g factors and hyperfine structure constants for a 4d 5 ion in rhombically distorted octahedra. Centre A or A ′ is assigned to the substitutional Ru 3+ on Ag + site associated with one nearest neighbor silver vacancy VAg in the [1 1 0] axis and one next nearest neighbor VAg in the [ 1 ¯ 0 0] axis due to charge compensation. Ru 3+ is found to undergo the off-centre displacement 0.022 or 0.017 Å along the [1 1 0] axis, while the halide ligands closest to the VAg move away from the vacancies by 0.030 or 0.005 Å in AgBr or AgCl, respectively, due to the electrostatic interactions of the VAg . Centre B or B ′ is ascribed to Ru 3+ associated with each nearest neighbor VAg in the [1 1 0] and [ 1 ¯ 1 ¯ 0] axes. The two axial ligands experience the displacement 0.036 or 0.015 Å along the Z (or [0 0 1]) axis, and the four planar ligands shift away from the vacancies by about 0.006 or 0.001 Å, respectively. Centre X or X ′ can be described as Ru 3+ associated with one nearest neighbor VAg and one next nearest neighbor VAg in the [1 1 0] and [0 0 1] axes, respectively. Ru 3+ may undergo the off-centre displacement 0.019 or 0.015 Å along the [1 1 0] axis, while the ligands closest to the VAg move away from the VAg by 0.022 or 0.006 Å. The present studies would be helpful to the investigations on the structures and properties for Ru 3+ in AgX and similar halides.