Another avenue of investigation that could be complementary to modern materials science software lies in the crystal chemistry rationale called "structural engineering". Recently, the body-centered tetragonal tet-C 4 (Fig. ) in space group I-4m2 was proposed by us as one of the simplest three-dimensional (3D) carbon networks to serve as a template for the design of other novel allotropes and chemical compounds . Using the TopCryst crystallography package , tet-C 4 was identified with dia (i.e. diamond-like) topology. Several chemical compounds also have a dia topology, as categorized in the Reticular Chemistry Structure Resource (RCSR) database .