Unique chains of alternating octahedral and tetrahedral cobalt(II) sites:: crystal structures of the novel chloro-bridged complexes [Co4(μ-Cl)6Cl2(thf)4(MeOH)2]n and [{Co4(μ-Cl)6Cl2(thf)4(H2O)2}•2THF]n
[Co-4(mu-Cl)(6)Cl-2(thf)(4)(MeOH)(2)](n), a catena-polycobalt(ii) complex with an unusual linear chain of octahedral/tetrahedral/octahedral cobalt sites, is obtained quantitatively from the reaction between cobalt chloride hydrate and trimethylorthoformate in THF.