Regular Double-Cube [Cr₇S₈]⁵⁺ in [Cr₇S₈(SCN)₄(NH₃)₁₄](HS): An Ideal Model Compound for Investigation of Geometrical Magnetic Frustration

The inorganic compound [Cr₇S₈(SCN)₄(NH₃)₁₄]­(SH) containing the [Cr₇S₈]⁵⁺ double-cube was synthesized by the hydrothermal method and structurally characterized by single crystal diffraction. Despite the fact that several transition metal based M₇X₈ double-cube-type compounds have been reported up to now, here the [Cr₇S₈]⁵⁺ double-cube is the most regular one and it has a strong antiferromagnetic geometric frustration (f = |θ_cw|/T_N > 33). Owing to the good separation of [Cr₇S₈]⁵⁺ units by the N-donor ligands, both long- and short-range magnetic order were absent in [Cr₇S₈(SCN)₄(NH₃)₁₄]­(SH) above 2 K; therefore, this is an ideal model compound for the investigation of geometrically magnetic frustration.