title: A new polymorph of 1,3-bis-(penta-fluoro-phen-yl)urea.
abstract: The title compound, C13H2F10N2O, has been previously described in the space group Pbca with Z = 8 [Jai-nhuknan et al. (1997 ▶). Acta Cryst. C53, 455-457]. The current P212121 polymorph was obtained from a tetra-hydro-furan solution. The penta-fluoro-phenyl rings make dihedral angles of 50.35 (6) and 54.94 (6)° with the urea fragment, in close accord with those reported for the first polymorph. In the crystal, both of the N-H groups donate H atoms to the same carbonyl O atom, forming a one-dimensional mol-ecular array along the a axis. There are close contacts between perfluoro-phenyl C atoms within the array [3.228 (3) Å] and halogen bonds are also observed between the arrays [F⋯F = 2.709 (2) and 2.7323 (18) Å].
authors: Department of Material Science and Chemistry, Wakayama University, Sakaedani, Wakayama, 640-8510, Japan.
authors: Tsunehisa
authors: T
authors: Okuno
references: Acta Crystallogr A. 2008 Jan;64(Pt 1):112-22
references: 18156677