Solvothermal synthesis was used to create a low-dimensional iron(II) chloride formate compound, NH4FeCl2(HCOO), that exhibits interesting magnetic properties. NH4FeCl2(HCOO) crystallizes in the monoclinic space group C2/c (No. 15) with a = 7.888(1) angstrom, b = 11.156(2) angstrom, c 6.920(2) angstrom, and beta = 108.066(2)degrees. The crystal structure consists of infinite zigzag chains of distorted Fe2+-centered octahedra linked by mu(2)-Cl and syn-syn formate bridges, with interchain hydrogen bonding through NH4+ cations holding the chains together. The unique Fe2+ site is coordinated by four equatorial chlorides at a distance of 2.50 angstrom and two axial oxygens at a distance of 2.08 angstrom. Magnetic measurements performed on powder and oriented single-crystal samples show complex anisotropic magnetic behavior dominated by antiferromagnetic interactions (T-N = 6 K) with a small ferromagnetic component in the direction of chain propagation. An anisotropic metamagnetic transition was observed in the ordered state at 2 K in an applied magnetic field of 0.85-3 T. Fe-57 Mossbauer spectroscopy reveals mixed hyperfine interactions below the ordering temperature, with strong electric field gradients and complex noncollinear arrangement of the magnetic moments.