Fig. 1: Crystal structure of (a-c) α-ATB4 and (d-f) β-ATB4.
From: Prediction of Van Hove singularity systems in ternary borides

a, d The network in the boron layer forms (5,7) rings. b, e The network in the metal layer. Metal A forms 6 membered-ring framework, and T forms a dimer. c, f Side view of metal and boron layers. Red shows the A site; Blue shows the T site; Green shows B atoms.