Sodium Bis(dipicolinato)ferrate(III) Dihydrate

The Fe centre in Na[Fe(C 7 H 3 NO 4 ) 2 ].2H 2 O is surrounded by an approximately octahedral arrangement of two pyridine N and four carboxylate O atoms from the two dipicolinate ligands (dipicolinic acid is 2,6-pyridine-dicarboxylic acid). The mean Fe-N and Fe-O bond distances are 2.05 and 2.02 A, respectively. The complex units are bridged by Na + ions which are coordinated to four carboxylate O atoms (of which three are not used for Fe chelation) and to two water molecules. The six donor O atoms form a distorted octahedron around the Na + ion with the water molecules trans to each other