Potassium N-(6-amino-3,4-dihydro-3-methyl-5-nitroso-4-oxopyrimidin-2-yl)-(S)-aspartate N-(6-amino-3,4-dihydro-3-methyl-5-nitroso-4-oxopyrimidin-2-yl)-(S)-aspartic acid 4.88-hydrate: a two-dimensional coordination polymer.

In the title compound, K(+).C(9)H(10)N(5)O(6)(-).C(9)H(11)N(5)O(6).4.88H(2)O, the cations are eight-coordinate. There is a one-dimensional coordination-polymer substructure, built from K and O atoms only, in the form of chains of distorted confacial octahedra, and these are linked into sheets by the neutral organic ligand. The sheets are linked into a single framework by a combination of N-H.O and O-H.O hydrogen bonds.