Table 1 Calculated and observed Cr–O and Cr–Fe distances relevant to chromate adsorption onto Fe-oxides and Fe-hydroxides. Experiment data from other studies on goethite [22] and hematite [46] are shown
From: Density functional theory modeling of chromate adsorption onto ferrihydrite nanoparticles
| Cr–O | Cr–O(Fe) | Cr–O(H) | Cr–Fe | |
|---|---|---|---|---|
| Experiment (this study) | 1.67 | 3.35–3.58 | ||
| Experiment [22, 46] | 1.64–1.68 | – | – | 3.30–3.60 |
| Outer-sphere | ||||
| Periodic | 1.64 | – | 1.77 | 5.27 |
| M06-2x/6-31G(d) | 1.57 | – | 1.80 | 4.17 |
| M06-2x/6-311+G(d,p) | 1.57 | – | 1.82 | 4.95 |
| B3LYP/6-31G(d) | 1.60 | – | 1.80 | 4.42 |
| B3LYP/6-311+G(d,p) | 1.60 | – | 1.83 | 4.54 |
| PBE0/6-311+G(d,p) | 1.59 | – | 1.81 | 5.80 |
| Mono(A) | ||||
| Periodic | 1.66 | 1.70 | – | 3.54 |
| M06-2x/6-31G(d) | 1.60 | 1.66 | – | 3.39 |
| M06-2x/6-311 + G(d) | 1.61 | 1.67 | – | 3.37 |
| B3LYP/6-31G(d) | 1.63 | 1.69 | – | 3.44 |
| B3LYP/6-311+G(d,p) | 1.63 | 1.69 | – | 3.40 |
| PBE0/6-311+G(d,p) | 1.61 | 1.68 | – | 3.35 |
| Mono(B) | ||||
| Periodic | 1.66 | 1.70 | – | 3.43 |
| Bi(A) | ||||
| Periodic | 1.65 | 1.70 | – | 3.29 |
| M06-2x/6-31G(d) | 1.57 | 1.68 | – | 3.19 |
| M06-2x/6-311+G(d,p) | 1.57 | 1.68 | – | 3.23 |
| B3LYP/6-31G(d) | 1.60 | 1.68 | – | 3.23 |
| B3LYP/6-311+G(d,p) | 1.60 | 1.69 | – | 3.26 |
| PBE0/6-311+G(d,p) | 1.59 | 1.68 | – | 3.22 |
| Bi(B) | ||||
| Periodic | 1.65 | 1.69 | – | 3.26 |
| M06-2x/6-311+G(d,p) | 1.59 | 1.66 | – | 3.40 |
| B3LYP/6-311+G(d,p) | 1.62 | 1.68 | – | 3.48 |
| PBE0/6-311+G(d,p) | 1.61 | 1.66 | – | 3.44 |