A series of isostructural lanthanide phosphonocarboxylate frameworks {(H3O)3[Ln7(pbpdc)6(DMF)4(H2O)3]·4H2O}n (named as LnPCF, Ln = Tb, Eu and Gd, H4pbpdc = 4'-phosphono-[1,1'-biphenyl]-3,5-dicarboxylic acid) were solvothermally synthesized and characterized by single crystal X-ray...