14.9 14.2 a Ref. b DFT-predicted. c Ref. Table provides the results for the dabco compounds. It shows that substitution of ReO 4 with IO 4 reduces the piezoelectric coefficients, which was also found for the quinuclidinium compounds. However, the d 24 value, which drops from 84 to 63 pC/N, remains sizeable. The substitution of ReO 4 with IO 4 increases the spontaneous polarization from 8.0 µC/cm 2 to 11.5 µC/cm 2 . Both the anisotropy and polarization decreased due to the same substitution for the quinuclidinium compounds. The different effect of the substitution on the piezoelectric anisotropy can be linked to the different crystal structures and the mechanisms for the shear piezoelectric response, where the rotational response is more pronounced for the quinuclidinium compounds than in the dabco case.