The low-temperature structure of the title compound, C(4)H(8)N(2)O, is ordered, whereas the central methyl-ene groups is disordered in the reported room-temperature structure. The molecule lies across a mirror plane; adjacent mol-ecules are linked by an N-H⋯O hydrogen bond into a chain.
* Title and MeSH Headings from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.