[Ni(HF2)(3-Clpy)4]BF4 (py = pyridine): evidence for spin exchange along strongly distorted F···H···F- bridges in a one-dimensional polymeric chain.

[Ni(HF2)(3-Clpy)4]BF4 (py = pyridine) is a simple one-dimensional (1D) coordination polymer composed of compressed NiN4F2 octahedra that form chains with bridging HF2– ligands. In spite of significant distortion of the HF2– bridge, a quasi-1D antiferromagnetic (AFM) behavior was observed with JFHF = 4.86 K.