Crystal structure and magnetic properties of the layered hybrid organic–inorganic compounds M ₂(OH)₂(C₁₄H₈O₄) (M = Mn, Fe)

The structure of M 2(OH)2(bpdc) (bpdc = biphenyl dicarboxylate, C14H8O4) is distinct from that of the isoreticular compounds M 2(OH)2(bdc) (bdc = benzene dicarboxylate, C8H4O4) (M = Mn, Fe), in the sense that no disorder of the bpdc molecules from one layer to the other needs to be considered. The global symmetry is lower in the bpdc compounds (P 1) than in the bdc compounds (C2/m). Both Mn2(OH)2(bpdc) and Fe2(OH)2(bpdc) order magnetically at 36.8 and 46.5 K, respectively, and can be considered as uncompensated antiferromagnets, whereas Mn2(OH)2(bdc) (Néel temperature T N = 38.5 K) and Fe2(OH)2(bdc) (T N = 66 K) are compensated antiferromagnets.