A multistep synthesis for 2-(2-pyridyl-N-oxide) ethylphosphonic acid 6-H-2 is described along with its spectroscopic (IR, NMR) data and a single-crystal X-ray diffraction structure analysis. Combination of the ligand with Nd(OH)(3) results in the formation of a complex Nd(6-H)(3). Single-crystal X-ray diffraction analysis reveals a three-dimensional crystal network generated by hydrogen-bonded chains along the crystallographic c axis. The hydrogen bonds are formed between phosphonic acid anion (6-H)(-1) protons on one chain and pyridyl N-oxide oxygen atoms in neighboring chains. The asymmetric unit contains 1/3[Nd(6-H)(3)] and there are two unique Nd(111) atoms, each with point symmetry. As a result, each Nd(III) ion is bound to six (6-H)(-1) ligands and the symmetry about the Nd(111) ion is octahedral with each vertex occupied by a phosphonate oxygen atom. The Nd-O bond lengths are essentially identical: Nd(1)-O(3), 2.336 (1) angstrom; Nd(2)-O(4), 2.340 (1) angstrom. The monoanionic ligand (6-H)(-1), therefore, serves to bridge the unique Nd(III) centers.