Ammonium trans-2-butenoate, NH4(O2CCH=CHCH3) 5 crystallizes in a similar fashion to metal two-dimensional coordination polymers, and thus is a candidate for facile radiation-induced solid-state reactions. The tetrahedral coordination of the ammonium is an obvious consequence of hydrogen bonding, but the relatively long N(...)0 distance (compared to a Group 1A metal) leads to repeat distances along the bilayer of ca. 4.7 angstrom. Interlayer contacts appear to be suitable for a radiation-induced Michael addition to occur. However, as observed for other nonmetal salts (e.g., those of propynoic acid), the material is stable to gamma-ray doses up to 336 kGy.