Redetermination at 180 K of a layered lanthanide–organic framework

The asymmetric unit of the title compound, poly[(μ(4)-{[bis­(hydrogen phospho­natometh­yl)aza­nium­yl]meth­yl}phospho­nato)lanthanum(III)], [La(C(3)H(9)NO(9)P(3))](n), comprises an La(3+) center and a H(3)nmp(3−) anion (where H(3)nmp(3−) is a residue of partially deprotonated nitrilo­tris­(methyl­ene­phospho­nic acid), namely {[bis­(hydrogen phospho­natometh­yl)aza­nium­yl]meth­yl}­phos­pho­nate). This study concerns a structural redetermination using single-crystal X-ray diffraction data, collected at the low temperature of 180 K, of a recently investigated material whose structural details have been proposed from powder X-ray diffraction studies [Silva et al. (2011 ▶). J. Am. Chem. Soc. 133, 15120–15138]. The main difference between the two models rests on the position of the H atoms. While two H atoms were modeled as attached to the same phospho­nate group in the powder determination, in the current model, the same H atoms are instead distributed among two of these groups. The sample studied was an inversion twin.