This includes reducing the cation density or decreasing the valency of the anionic species. Such strategic adjustments yield a discernible reduction in the rotational activation energy (E r a ), as illustrated in Fig. ). This multifaceted approach ultimately leads to a significant decrease in the critical T tran , as exemplified by the sequence T tran (C 2 B 10 H 12 )< T tran (LiCB 11 H 12 )< T tran (Li 2 B 12 H 12 ). These observations underscore the intricate interplay of structural and compositional factors in governing the phase transition behavior of complex hydrides.