The molecular conformation of the title compound has been defined by an X-ray crystallographic analysis from diffractometer data measured with Cu Kα radiation. The monoclinic crystals belong to the space group P21/n with a 16.256(6), b 6.130(1), c 9.812(2) Ǻ, β 96.42(2)°, and Z 2. The structure was solved by direct methods and refinement converged to give an R of 0.071 for the 1221 observed terms. Unlike other 1,3,5,7- substituted eight-membered heterocyclic compounds, the molecule adopts a chair conformation and has exact C1 symmetry. All the trichloromethyl substituents are equatorial.