Crystal structure of a samarium(III) nitrate chain cross-linked by a bis-carbamoyl­methyl­phosphine oxide ligand

In the title compound poly[aqua­bis­(μ-nitrato-κ(4) O,O′:O,O′′)tetra­kis­(nitrato-κ(2) O,O′){μ(4)-tetra­ethyl [(ethane-1,2-diyl)bis(aza­nedi­yl)bis­(2-oxo­ethane-2,1-di­yl)]di­phospho­nate-κ(2) O,O′}disamarium(III)], [Sm(2)(NO(3))(6)(C(14)H(30)N(2)O(8)P(2))(H(2)O)](n), a 12-coordinate Sm(III) and a nine-coordinate Sm(III) cation are alternately linked via shared bis-bidentate nitrate anions into a corrugated chain extending parallel to the a axis. The nine-coordinate Sm(III) atom of this chain is also chelated by a bidentate, yet flexible, carbamoyl­methyl­phoshine oxide (CMPO) ligand and bears one water mol­ecule. This water mol­ecule is hydrogen bonded to nitrate groups bonded to the 12-coordinate Sm(III) cation. The CMPO ligand, which lies about an inversion center, links neighboring chains along the c axis, forming sheets parallel to the ac plane. Hydrogen bonds between the amide NH group and metal-bound nitrate anions are also present in these sheets. The sheets are packed along the b axis through only van der Waals inter­actions.