Bis(2,1,3-benzotelluradiazolidyl)2,1,3-benzotelluradiazole: a pair of radical anions coupled by Te⋯N chalcogen bonding

Reduction of 2,1,3-benzotelluradiazole (3) yielded a crystalline solid that features a trimeric dianion formally composed of two [3]˙- and one 3 bridged by unusually asymmetric TeN chalcogen bonds. The solid is diamagnetic due to strong antiferromagnetic coupling, as revealed by CASSCF/CASPT2 and BS-DFT.