Some chemical parameters for Ga3+, Fe3+, Al3+, and In3+
| Parameter | Unit | Ga3+ | Fe3+ high spin | Al3+ | In3+ | Ref. |
|---|---|---|---|---|---|---|
| Ionic radius (octahedral) | Å | 0.620 | 0.645 | 0.535 | 0.800 | 1 |
| Ionic radius (tetrahedral) | Å | 0.47 | 0.49 | 0.39 | 0.62 | 1 |
| Ionization potential (4th ionization potential) | eV | 64 | 54.8 | 119.99 | 54 | 2 |
| Electron affinity (3rd ionization potential) | eV | 30.71 | 30.65 | 28.45 | 28.03 | 2 |
| Absolute hardness (Pearson) | eV | 17 | 12.08 | 45.77 | 13 | 2 |
| Electronegativity (Pauling) | Pauling units | 1.81 | 1.83 | 1.61 | 1.78 | 3 |
| Metal-oxygen bond dissociation energy | KJ mol−1 | 353.5 | 390.4 | 511 | 320.1 | 4 |
| First metal-hydroxide formation constant: K 1 = [MOH2−]/[M3+][OH−] | logK 1 | 11.4 | 11.81 | 9.01 | 10.0 | 5 |
| Tendency to ionic bonding (HA) | none | 7.69 | 7.22 | 10.50 | 6.30 | 6 |
References: (1) Shannon, 1976; (2) Pearson, 1988; (3) Huheey et al., 1993; (4) Kerr, 1996; (5) Smith and Martell, 1976; (6) Hancock and Marsicano, 1980.