N,N'-Bis[tris(hydroxymethyl)methyl]-ethanediamide: six O-H...O hydrogen bonds generate only a two-dimensional structure

Molecules of the title compound, C10H20N2O8, adopt a conformation which is almost centrosymmetric. The molecules are disordered over two sets of sites with an occupancy ratio of 0.94:0.06. In the major form, there are two intramolecular OD H . . .O hydrogen bonds [O . . .O 2.756 (4) and 2.765 (4) Angstrom; O- H . . .O 144 and 146 degrees], in which the two amidic O atoms act as acceptors. In addition, there are four intermolecular OD H . . .O hydrogen bonds [O . . .O 2.650 (3)-2.666 (3) Angstrom; O- H . . .O 158-171 degrees]; these link each molecule to six others in a continuous sheet structure which contains five distinct ring motifs, two of the S(7) type, two of the R-3(3) (10) type and one of the R-2(2) (22) type.