The following sections present the computed properties of 11 plastic ionic molecular crystals. Four different types of plastic crystals were considered: 1. Quinuclidinium compounds, 2. Dabco-compounds, 3. (R)-OH-Q-compounds, and 4. C[NH 2 ] 3 -compounds. They all consist of one organic cation per inorganic anion and are quite representative of the broad range of ferroelectric ionic plastic crystal compositions that have emerged in recent years . The quinuclidinium and dabco compounds have globular organic cations and tetrahedral anions, where the central atom is coordinated by oxygen. The (R)-OH-Q-compounds also have globular cations, but halogen anions. Finally, the C[NH 2 ] 3 -compounds have planar organic cations and anions with tetrahedral geometry.