The crystal structures of iron and cobalt pyridine (py)–sulfates, [Fe(SO(4))(py)(4)](n) and [Co(3)(SO(4))(3)(py)(11)](n)

The solid-state structures of two metal–pyridine–sulfate compounds, namely catena-poly[[tetra­kis­(pyridine-κN)iron(II)]-μ-sulfato-κ(2) O:O′], [Fe(SO(4))(C(5)H(5)N)(4)](n), (1), and catena-poly[[tetra­kis­(pyridine-κN)cobalt(II)]-μ-sulfato-κ(2) O:O′-[tetra­kis­(pyridine-κN)cobalt(II)]-μ-sulfato-κ(3) O,O′:O′′-[tris­(pyridine-κN)cobalt(II)]-μ-sulfato-κ(2) O:O′], [Co(3)(SO(4))(3)(C(5)H(5)N)(11)](n), (2), are reported. The iron compound (1) displays a polymeric structure, with infinite chains of Fe(II) atoms adopting octa­hedral N(4)O(2) coordination environments that involve four pyridine ligands and two bridging sulfate ligands. The cobalt compound (2) displays a polymeric structure, with infinite chains of Co(II) atoms. Two of the three Co centers have an octa­hedral N(4)O(2) coordination environment that involves four pyridine ligands and two bridging sulfate ligands. The third Co center has an octa­hedral N(3)O(3) coordination environment that involves three pyridine ligands, and two bridging sulfate ligands with one sulfate chelating the cobalt atom.