Lone-pair self-containment in tellurite tubes: hydrothermal syntheses and structures of BaTe(3)O(7) and BaTe(4)O(9)

The hydrothermal syntheses and single-crystal structures of BaTe3O7 and BaTe4O9 are reported. These closely related new phases, which can be regarded as the n = 3 and 4 members of the BaTenO2n+1 family, are built up from infinite, tubular, columns of Te/O polyhedra (6 ring loops for BaTe3O7 and 8 ring loops for BaTe4O9) with barium cations completing the structures. The tubes represent a novel way to accommodate the lone pair of electrons associated with each TeIV species and suggest the possibility of redox intercalation chemistry for these types of material.