A model Hamiltonian for the orientational order of TMCM cations was build using a model inspired by the pair mode concept introduced by Li et al. . Using the hexagonal setting of the high temperature phase, the structure of TMCMCdCl 3 consists of one-dimensional face-sharing CdCl 6 -octahedra along the c-direction with TMCM molecules located around the 2c Wyckoff positions. Assuming that the molecular mirror plane is retained in the solid state and coincides with the mirror plane or the local 6m2 of the Wyckoff site, there are six different molecular orientations per site.