(Z)-9-(1,2-Dichloro­vin­yl)-9H-carbazole

There are two independent mol­ecules in the asymmetric unit of the title compound, C₁₄H₉Cl₂N, in which the dihedral angles between the dichloro­vinyl unit (r.m.s. deviations = 0.0003 and 0.0009 Å), and the carbazole ring are 87.77 (3) and 72.90 (3)°.

A new polymorph of 1,3-bis­(penta­fluoro­phen­yl)urea

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 tetra­hydro­furan solution. The penta­fluoro­phenyl 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 mol­ecular array along the a axis. There are close contacts between perfluoro­phenyl 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].