5-Cyclo-hexyl-4-methyl-1H-pyrazol-3(2H)-one monohydrate

In the title compound, C(10)H(16)N(2)O·H(2)O, the cyclo-hexane ring is in a chair conformation and its least-squares plane makes a dihedral angle of 53.68 (5)° with the approximately planar pyrazole ring [maximum deviation = 0.034 (1) Å]. Pairs of inter-molecular N-H⋯O hydrogen bonds form inversion dimers between neighbouring pyrazolone mol-ecules, generating R(2) (2)(8) ring motifs. The pyrazolone and water mol-ecules are further linked by inter-molecular N-H⋯O, C-H⋯O and O-H⋯O hydrogen bonds into two-dimensional sheets parallel to the bc plane.