Dimorphism in 3'-aminocyclohexanespiro-5'-hydantoin.

The title compound [systematic name: 1'-aminocyclohexanespiro-4'-imidazole-2',5'(3'H,4'H)-dione], C8H13N3O2, has been synthesized and was found to crystallize in two different structures, both monoclinic and both with the same P2(1)/c space group. In the first structure, there are two molecules in the asymmetric unit, one of which uses all of its hydrogen-bond donors and acceptors and forms undulating layers, while the other forms chains propagating perpendicular to the layers. In the second structure, there is only one independent molecule and the packing is based on a chain structure mediated by hydrogen bonding between the hydantoin moieties and further grouped into hydrophilic layers separated by layers of the hydrophobic cyclohexyl groups.