Poly[guanidinium [tri-μ-formato-κ(6) O:O′-formato-κ(2) O,O′-yttrium(III)]]

In the title coordination polymer, {(CH(6)N(3))[Y(CHO(2))(4)]}(n), the yttrium(III) ion is coordinated by one O,O-bidentate formate ion and six μ(2) bridging formate ions, generating a square-anti­prismatic YO(8) coordination polyhedron. The bridging formate ions connect the metal ions into an anionic, three-dimensional network. Charge compensation is provided by guanidinium ions, which inter­act with the framework by way of N—H⋯O hydrogen bonds. The guanidine molecules reside in porous channels of 3.612 by 8.189 Å, when considering the van der Waals radii of the nearest atoms (looking down the a-axis).