Bis(μ-2-sulfonatobenzoato)bis[(1,10-phenanthroline)lead(II)] dihydrate

In the title centrosymmetric dimer, [Pb-2(sbc)(2)(phen)(2)].2H(2)O [sbc is the 2-sulfonatobenzoate dianion (C7H4O5S) and phen is 1,10-phenanthroline (C12H8N2)], each Pb-II ion is six-coordinated by four O atoms, viz. carboxylate and sulfonate O atoms from two sbc anions, and two N atoms from a 1,10-phenanthroline ligand. One 1,10- phenanthroline ligand and the carboxylate group of one sbc ligand are chelated to each Pb-II cation, and the sulfonate group of the other sbc unit is monodentate. One O atom of the chelated carboxylate group also bridges to the other Pb-II cation, so that each pair of Pb-II ions is bridged by two sbc anions and has the same coordination environment, forming a dinuclear ring. Each pair of Pb-II ions is thus connected by two different kinds of bridges, namely a carboxylate short bridge and a carboxylate-sulfonate long bridge. There is also a special position of 1 site symmetry at the centre of the two Pb-II cations.