Neutron diffraction study of the magnetic structures of manganese succinateMn(C4H4O4): A complex inorganic-organic framework
The antiferromagnetic structures of the Mn succinate framework, $\text{Mn}({\text{C}}_{4}{\text{H}}_{4}{\text{O}}_{4})$, have been determined using neutron diffraction. The structure comprises alternating layers containing chains of edge-sharing $\text{Mn}(\text{II}){\text{O}}_{6}$ octahedra and sheets of corner-sharing $\text{Mn}(\text{II}){\text{O}}_{6}$ octahedra, respectively, with a layer separation of $\ensuremath{\sim}7.5\text{ }\text{\AA{}}$. At 10 K the edge-sharing ${\text{MnO}}_{6}$ octahedral chains order antiferromagnetically into a collinear sinusoidal spin structure with a propagation vector ${k}_{2}=(0,\ensuremath{-}0.5225,0)$, in which individual edge-sharing ${\text{MnO}}_{6}$ chains are ferromagnetically ordered. The sheets of corner-sharing ${\text{MnO}}_{6}$ octahedra order magnetically at 6 K, adopting the antiferromagnetic structure expected for a square arrangement of cations with a propagation vector ${k}_{8}=(\ensuremath{-}1,0,1)$. The ordering of these sheets at a lower temperature than the chains is consistent with their longer nearest-neighbor superexchange pathway. The magnetic structure of the edge-sharing layers is unaffected by the 6 K phase transition, indicating that the orderings of the two different layers are essentially independent of each other.