Structure of (E)-5-(methoxymethylene)-2,4-imidazolidinedione

C5H6N2O3, Mr = 142.11, monoclinic, P2(1)/n, a = 3.862 (1), b = 16.329 (2), c = 10.088 (1) A, beta = 98.77 (2) degrees, V = 628.7 (2) A3, Z = 4, Dx = 1.50 g cm-3, lambda(Mo K alpha) = 0.71069 A, mu = 1.18 cm-1, F(000) = 296, T = 296 K, R = 0.035 for 1124 independent reflections with I greater than 3 sigma(I). The structure is a hydantoin derivative with a methoxymethylene group substituted at the 5-position. Excluding the H atoms, the molecule is planar to within 0.032 A. All of the N and O atoms are involved in an intermolecular hydrogen-bonding network via N--H...O and C--H...O interactions. The packing arrangement is a linear ribbon motif with the ribbons stacked to form the short a axis.