Table 3. Differences in the hydrogen-bond acidity, Δα, and the hydrogen-bond basicity, Δβ, for constituent cations and anions of ionic liquid mixture series 1–11. Values were determined either experimentally (‘exp’), or from the arithmetic mean of a series of computational literature values (‘ave’)58,61–63 .
| Ionic liquid mixture series | Δα ave | Δα ave | Δβ exp | Δβ exp |
| 1 [C4C1im]Cl[OTf] | — | — | 0.40 | 0.40 |
| 2 [C4C1im][MeSO4][Me2PO4] | — | — | 0.36 | 0.50 |
| 3 [C4C1im][OTf][NTf2] | — | — | 0.21 | 0.22 |
| 4 [C4C1im][(HOC2)3C1N][MeSO4] | 0.24 | 0.47 | — | — |
| 5 [C4C1im][MeSO4][NTf2] | — | — | 0.40 | 0.40 |
| 6 [C4C1pyrr][NTf2][Me2PO4] | — | — | 0.76 | 0.90 |
| 7 [C4C1im][NTf2][Me2PO4] | — | — | 0.76 | 0.90 |
| 8 [C4C1im][Me-DBU][MeSO4] | 0.37 | 0.39 | — | — |
| 9 [C4C1im][C1C1C1pz][OTf] | 0.10 | 0.10 | — | — |
| 10 [C4C1im][Me-DBU][MeSO4][NTf2] | 0.37 | 0.39 | 0.40 | 0.40 |
| 11 [C4C1im][C4C1pyrr][OTf][NTf2] | 0.16 | 0.18 | 0.21 | 0.22 |