A one-dimensional (1D) chain compound [Fe(en)3]3(FeSe2)4Cl2 (en = ethylenediamine), featuring tetrahedral FeSe2 chains separated by [Fe(en)3] 2+ cations and Clanions, has been synthesized by a low temperature solvothermal method using simple starting materials. The degree of distortion in the Fe-Se backbone is similar to previously reported compounds with isolated 1D FeSe2 chains. 57 Fe Mössbauer spectroscopy reveals the mixed-valent nature of [Fe(en)3]3(FeSe2)4Cl2 with Fe 3+ centers in the [FeSe2]chains and Fe 2+ centers in the [Fe(en)3] 2+ complexes. SQUID magnetometry indicates that [Fe(en)3]3(FeSe2)4Cl2 is paramagnetic with a reduced average effective magnetic moment, μeff, of 9.51 μB per formula, and a negative Weiss constant, θ, −10.9(4) K, indicating antiferromagnetic (AFM) nearest neighbor interactions within the [FeSe2]chains. Weak antiferromagnetic coupling between chains, combined with rather strong intrachain AFM coupling leads to spin-glass behavior at low temperatures, as indicated by a frequency shift of the peak observed at 3 K in AC magnetic measurements. A combination of [Fe(en)3] 2+ and Clions is also capable of stabilizing mixed-valent 2D Fe-Se puckered layers in the crystal structure of [Fe(en)3]4(Fe14Se21)Cl2, where Fe14Se21 layers have a unique topology with large open pores. Property measurements of [Fe(en)3]4(Fe14Se21)Cl2 could not be performed due to the inability to either grow large crystals or synthesize this material in single-phase form.

An isostructural series of transition metalformate-chloride-hydrate compounds, M 3 (OOCH) 5 Cl(OH 2 ) (M = Fe, Co, Ni), have been synthesized using a solvothermal method. These compounds crystallize in the chiral and polar space group P3 1 and are comprised of three different types of helical chains of edge-sharing M 2+ -centered octahedra. All three compounds undergo 3D ferrimagnetic ordering at low temperature, and the iron and cobalt analogues exhibit fieldinduced metamagnetic transitions. The magnetic structure was determined by neutron powder diffraction, revealing ferromagnetic intrachain coupling and antiferromagnetic interchain interactions, with the three chains arranged in a two-up/onedown triangular lattice. As all three chains contain one type of metal in the same spin state, these compounds are rare examples of homospin topological ferrimagnets.