Redetermination of [Gd(NO₃)₃(H₂O)₄]·2H₂O.

The crystal structure of the title compound, tetra-aqua-tris-(nitrato-κ²O,O')gadolinium(III) dihydrate, was redetermined from single-crystal X-ray data. In comparison with the first determination [Ma et al. (1991 ▶). Wuji Huaxue Xuebao, 7, 351-353], all H atoms could be located, accompanied with higher accuracy and precision. The Gd(III) atom shows a ten-coordination with three nitrate ligands behaving in a bidentate manner and the other positions being occupied by four water mol-ecules, forming a distorted bicapped square anti-prism. Two nitrate ions coordinate to the metal atom with similar bond lengths while the third shows a more asymmetric bonding behaviour. An intricate network of O-H⋯O hydrogen bonds, including the lattice water mol-ecules, stabilizes the crystal packing.