The quinuclidinium-based compounds were among the first ionic plastic crystals with which multi-axial ferroelectric switching of the polarization vectors were observed. The three ionic quinuclidinium-based compounds studied here are presented in Fig. . Two of them consists of quinuclidinium (HQ) cations and the inorganic anions ReO 4 and IO 4 , while the third consists of 4-fluoroquinuclodinium (F-Q) and ReO 4 . All three systems pack in similar side-centered crystal structures. The side-centered packing allows for monoclinic and orthorhombic Bravais lattices. HQReO 4 and HQIO 4 pack in the orthorhombic space group P mn2 1 , while HQIO 4 pack in the monoclinic P n space group. Note that while the F-Q cation in [F -Q]ReO 4 points in the c-axis direction, the direction of the HQ-cations is tilted in HQReO 4 , and likewise for HQIO 4 .