Bis(μ-adamantane-1,3-dicarboxyl-ato-κO,O:O,O)bis-[aqua-(3-carboxy-adam-antane-1-carboxyl-ato-κO)(1,10-phen-an-throline-κN,N')erbium(III)] dihydrate.

The asymmetric unit of the binuclear centrosymmetric title compound, [Er(2)(C(12)H(14)O(4))(2)(C(12)H(15)O(4))(2)(C(12)H(8)N(2))(2)(H(2)O)(2)]·2H(2)O, contains one Er(III) atom, one coordinated water mol-ecule, one 1,10-phenanthroline (phen) ligand, two differently coordinated adamantane-1,3-dicarboxyl-ate (H(2)L) ligands and one lattice water mol-ecule. The Er(III) ion is eight-coordinated by four O atoms from bridging L(2-), one O atom from HL(-), one O atom from the coordinated water and two N atoms from a phen ligand. Extensive O-H⋯O hydrogen-bonding inter-actions result in the formation of chains which are further linked into a layer-like network by π-π stacking inter-actions centroid-centroid distance = 3.611 (3) Å] between adjacent phen ligands belonging to neighbouring chains. The carboxy group of the HL(-) ligand is equally disordered over two positions.