The AB4 T-4 E-mode angular configuration space was generated following method of Canfield, et al., using the T-4-R "seed" polytope species, and its associated orthonormal e-symmetric angular-displacement basis, as shown in Fig. , In brief, the two components of the tetrahedral T-4 e-symmetric vibrational normal mode (E-mode) are used as an angular displacement basis and combined in a manner akin to that used to describe geometries in systems experiencing Jahn-Teller distortions. Two angular parameters are utilised with this approach with the angle ϕ determining the mixing of the two E-mode components and θ giving the magnitude of the angular displacement.