Crystal structure of rac-(3aR∗,9aS∗)-4,4,4-trichloro-1,2,3,3a,4,9a-hexahydro-4λ5,9λ4-cyclopenta[4,5][1,3]tellurazolo-[3,2-a]pyridine

The title compound, C10H12Cl3NTe, crystallizes with two crystallographically independent molecules (A and B) in the asymmetric unit. In each case, the coordination around the Te atom is distorted square-pyramidal, with the equatorial plane composed of the three Cl atoms and the C atom of the pyridinium ring. The Te atom is displaced from the meansquare plane by 0.1926 (7) and 0.1981 (8) Å, in molecules A and B, respectivly, away from the apical C atom. The bond lengths from the Te atom to the two Cl atoms arranged trans to each other [2.5009 (7)/2.5145 (7) and 2.5184 (7)/2.5220 (8) Å in molecules A and B, respectivly] are substantially shorter than the third Te-Cl distance [2.8786 (7) and 2.8763 (7) Å in molecules A and B, respectivly]. The 1,3-tellurazole ring is almost planar (r.m.s. deviations of 0.042 and 0.045 Å in molecules A and B, respectivly). The cyclopentane rings in both molecules A and B adopt envelope conformations with the carbon atom opposed to the (Te)C-C(N) bond as the flap. In the crystal, molecules form centrosymmetric 2 + 2 associates via Te· ··Cl interactions [3.3993 (7) and 3.2030 (7) Å]. As a result of these secondary interactions, the Te atom attains a strongly distorted 5 + 1 octahedral environment. Further, the 2 + 2 associates are bound by weak C-H···Cl hydrogen bonds into a three-dimensional framework.