Table 1. Comparison of Lanthanide and Actinide +3 Aquo Ions Analyzed by EXAFSa.
| compound | metal soln concn | matrix | ionic radius (CN = 6)63 | CN | R [Å] | σ2 [Å2] | ΔE0 [eV] |
|---|---|---|---|---|---|---|---|
| Ac-aquo | 0.264 mM | 0.11 M HO3SCF3 | 1.12 | 10.9 ± 0.5 | 2.63(1) | 0.009 | -3.9 |
| LaIII(H2O)y31 | 0.2 M | pH 1 HO3SCF3 | 1.032 | 6.0 ± 0.5 | 2.560(9) | 0.007(1) | |
| 3.0 ± 0.5 | 2.66(2) | 0.0065(22) | |||||
| LaIII(H2O)y9 | 2–3 M | 0.25 M HCl | 1.032 | 9.2 ± 0.37 | 2.54(3) | 0.0090 | –7.3 |
| LaIII(H2O)y31 | 0.2 M | pH 1 HO3SCF3 | 1.032 | 6.0 ± 1.0 | 2.50(4) | 0.014(6) | |
| 3.0 ± 1.2 | 2.57(4) | 0.009(7) | |||||
| UIII(H2O)y6 | 1–10 mM | pH 0 HCl | 1.025 | 9.1 ± 0.6 | 2.52(1) | 0.009(1) | 12.8 |
| UIIIaq7 | 1 M HCl | 1.025 | 8.7 ± 0.9 | 2.56(1) | 0.10(1) | 2.1 | |
| NpIII(H2O)y6 | 0.5–2 mM | pH 0 HCl | 1.01 | 10.0 ± 1.2 | 2.51(1) | 0.009(1) | 7.2 |
| NpIIIaq7 | 1 M HCl | 1.01 | 9.8 ± 0.9 | 2.52(1) | 0.10(1) | 3.8 | |
| NpIIIaq8 | 4.7 mM | 1 M HClO4 | 1.01 | 9.0 ± 1.0 | 2.48(2) | ||
| PuIII(H2O)y49 | 20 mM | 0.01 M LiCl | 1 | 10.2 ± 1.1 | 2.510(6) | 0.010 | –10.4 |
| PuIII(H2O)y9 | 10 mM | 0.01 M LiCl | 1 | 9.2 ± 0.33 | 2.510(6) | 0.010 | –10.4 |
| PuIII(H2O)y6 | 0.8–2 mM | pH 0 HCl | 1 | 9.9 ± 0.3 | 2.49(1) | 0.009(1) | 7.0 |
| PuIIIaq10 | 0.01 mM | 1 M HClO4 | 1 | 8.6 ± 0.2 | 2.50(2) | 0.0083 | 7.16 |
| PuIIIaq7 | 1 M HCl | 1 | 9.9 ± 0.9 | 2.51(1) | 0.10(1) | 2.3 | |
| PuIIIaq50 | 1 | 8–9 | 2.48 | ||||
| NdIII(H2O)y9 | 2–3 M | 0.25 M HCl | 0.983 | 9.5 ± 0.37 | 2.49(3) | 0.0090 | –8.2 |
| NdIII(H2O)y52 | HClO4 | 0.983 | 9.5 | 2.51 | 0.0091 | ||
| Am-aquo4 | 4.8 mM | 0.11 M HO3SCF3 | 0.975 | 9.5 ± 0.87 | 2.48(1) | 0.0088(9) | –4.71 |
| AmIII(H2O) y(11) | 1 mM | 0.025 M HClO4 | 0.975 | 8.3 ± 0.4 | 2.473(4) | 0.0071(6) | –12.2 |
| AmIII(H2O) y(9) | 10 mM | 0.25 M HCl | 0.975 | 10.3 ± 0.33 | 2.480(6) | 0.009 | –8.7 |
| AmIII(H2O) y(12) | 7.9 mmol kg–1 | 0.03 M NaClO4 (pH 3.5) | 0.975 | 9.0 ± 0.0 | 2.47(1) | 0.0074(5) | 7.2 |
| AmIIIaq7 | 1 M HCl | 0.975 | 9.5 ± 0.9 | 2.51(1) | 0.10(1) | 1.0 | |
| CmIII(H2O)y9 | 10 mM | 0.25 M HCl | 0.97 | 10.2 ± 0.33 | 2.450(6) | 0.009 | –13.0 |
| CmIII(H2O)y13 | 0.523 M | 1 M HClO4 | 0.97 | 7.0 ± 0.4 | 2.469(7) | 0.0071(8) | –2.0 |
| BkIII(H2O)y14 | 0.47 mM | 1 M HClO4 1 M | 0.96 | 9.0 ± 0.6 | 2.43(2) | 0.009(2) | 2.7 |
| SmIII(H2O)y52 | HClO4 | 0.958 | 9.3 | 2.45 | 0.0077 | ||
| CfIIIaq7 | 1 M HCl | 0.95 | 9.5 ± 0.9 | 2.44(1) | 0.10(1) | 2.5 | |
| CfIII(H2O)y15 | 2.2 mM | 0.1 M HClO4 | 0.95 | 8.0 ± 0.0 | 2.42(1) | 0.0077(1) | 1.76 |
| CfIII(H2O)y16 | 1.67 M | 1 M HCl | 0.95 | 8.5 ± 1.5 | 2.42(2) | 0.0095(1) | 1.4 |
| GdIII(H2O)y52 | HClO4 | 0.938 | 7.6 | 2.41 | 0.0066 |
a
Data in bold are from this study, and data are presented in the order of decreasing ionic radius.63