title: 2-Pyridone: monoclinic polymorph.
abstract: The asymmetric unit in the title compound, C(5)H(5)NO, comprises two independent but virtually identical mol-ecules of 2-pyridone, and represents a monoclinic polymorph of the previously reported ortho-rhom-bic (P2(1)2(1)2(1)) form [Penfold (1953 ▶). Acta Cryst.6, 591-600; Ohms et al. (1984 ▶). Z. Kristallogr.169, 185-200; Yang & Craven (1998 ▶). Acta Cryst. B54, 912-920]. The independent mol-ecules are linked into supra-molecular dimers via eight-membered {⋯HNC(O)}(2) amide synthons in contrast to the helical supra-molecular chains, mediated by {⋯HNC(O)} links, found in the ortho-rhom-bic form.
authors.forename: Hadi D
authors.initials: HD
authors.lastname: Arman
authors.forename: Pavel
authors.initials: P
authors.lastname: Poplaukhin
authors.forename: Edward R T
authors.initials: ER
authors.lastname: Tiekink