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(共16张PPT)
Lanthanide and Actinide
The Core-Like Behavior of f Electrons
f electron density is almost totally confined to the inner regions of the lanthanoid ion
Separation
Redox：
Ln3+
Ce3+
H2O2 or O2
Ln3+
Ce4+
pH=0.7~1.0
Ln3+
Ce(OH)4↓
Ln(OH)3 ↓
Ln3+
Eu3+
Zn-Hg
Ln3+
Eu2+
NH3·H2O
NH4Cl
Ln(OH)3 ↓
Eu2+
pH=5~7
Extraction
Spectral Features
the spectral bands are very sharp as compared with 'd-d' transitions in d-block complexes.
The sharpness of these f-f transitions follows immediately from the core-like character of the f shell.
It interacts little with the bond orbitals and other aspects of the environment - hence the small ligand-field strength - and so the range of interaction throughout a molecular vibration is also small.
The intensities of these transitions are also small.
Color of aqueous lanthanide Ions
La3+ colorless Lu3+
Ce3+ colorless Yb3+
Pr3+ green Tm3+
Nd3+ pink Er3+
Pm3+ pinkish yellow Ho 3+
Sm3+ yellow Dy3+
Eu3+ colorless Tb3+
Gd3+ colorless Gd3+
f－f transition
Ce
Pr
Nd
Pm
Sm
Eu
Gd
Tb
Dy
Ho
Er
Tm
Yb
Lu Colorless
Green
Lilac
Pink
Yellow
Very pale pink
Colorless
Very pale pink
Yellow
Yellow
Rose-pink
Pale green
Colorless
Colorless
Ln(OH)3 → LnO(OH) → Ln2O3
Ce(OH)4 is brown (Ksp=4×10－51)，pH: 0.7~1.0，
used in Ce separation
La(OH)3 → Lu(OH)3
Acidity
Ksp: 10－9 10－24
Precipitation
pH: 7.82 6.30
△
△
Chloride, sulfate, nitrate: soluble
Oxalate, carbonate, fluoride, phosphate: low solubility
LnOCl+HCl↑+5H2O
Ln2O3+C+Cl2 → LnCl3+CO
Ln2O3+NH4Cl → LnCl3+NH3↑+H2O
Ln2O3+SOCl2 → LnCl3+SO2↑
△
LnCl3·6H2O ==
Ln2(C2O4)3 Ln2O3 +CO↑+CO2 ↑
Salts
△
2CeO2+8HCl == 2CeCl3 + Cl2 + 4H2O
2CeO2 + 2KI + 8HCl == 2CeCl3 + I2 + 2KCl + 4H2O

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