RESUMO
[1,4]Ditellurino[2,3-b:5,6-b']di-pyrazine represents the first reported [1,4]chalcogena[2,3-b:5,6-b']di-pyrazine containing a heavy chalcogens The asymmetric unit consists of three mol-ecules. In contrast to its sulfur analog, which is planar [Lynch et al. (1994 â¸) Cryst. Struct. Commun. 50,1470-1472], C8H4N4Te2 is folded along the Teâ¯Te axis to accommodate the larger chalcogenide atoms. The dihedral angle between the two Te2C2 rings of the central ring is 57.9° (mean of three). C-Te bond lengths range from 2.1105â (16)â Å to 2.1381â (17)â Å, in good agreement with those predicted by their covalent radii. All Te atoms are involved in inter-molecular Teâ¯N contacts, with distances in the range 2.894â (2) to 2.963â (2)â Å. These result in a spiral supra-molecular assembly, forming helical columns.