Ni3Cl2+x(OH)4‐x·2H2O: Structural, Thermal, Spectral, and Magnetic Properties in Dependence of the Chloride Content.

The previously unknown nickel chloride hydroxide phases Ni3Cl2+x(OH)4–x·2H2O (x = 0.26, 0.48, 0.82) have been synthesized in concentrated aqueous NiCl2 solutions and investigated in detail. Crystal structure determination from X-ray powder diffraction data revealed triple chains of distorted, edge-linked NiO6 and NiO3(O/Cl)3 octahedra as the main building blocks. The chains exhibit a layer-like configuration and therefore great structural similarity to nickel-layered hydroxy halides (Cl, Br, I) and β-Ni(OH)2. Increasing chloride content in Ni3Cl2+x(OH)4–x·2H2O leads to a reduction of the space group symmetry from C2/m (12) for x = 0.26 and 0.48 to P (2) for x = 0.82 and to distinct shifts in their thermal, spectral, and magnetic properties. Each solid exhibits a maximum magnetic susceptibility in the range 5.9–9.7 K, which indicates antiferromagnetic ordering. Positive Curie–Weiss temperatures, θ, were found, which points to predominantly ferromagnetic spin-exchange interactions. In addition, broad maxima of the magnetic susceptibility evidence a low-dimensional magnetic character as the most prominent feature of the magnetic properties of the investigated phases.