无机化学课件：28 Lanthanide

1、Lanthanide and ActinideThe Core-Like Behavior of f Electronsf electron density is almost totally confined to the inner regions of the lanthanoid ionSeparation Redox：Ln3+Ce3+H2O2 or O2Ln3+Ce4+pH=0.71.0Ln3+Ce(OH)4Ln(OH)3 Ln3+Eu3+Zn-HgLn3+Eu2+NH3H2ONH4ClLn(OH)3 Eu2+pH=57ExtractionSpectral Featuresthe s

2、pectral 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 s

3、trength - 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 IonsLa3+ colorless Lu3+Ce3+ colorless Yb3+Pr3+ green Tm3+Nd3+ pink Er3+Pm3+ pinkish yellow Ho 3+Sm3+ yellow Dy3+Eu3+ colorless Tb3

4、+Gd3+ colorless Gd3+ff transitionCe Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu ColorlessGreen 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=41051)，pH: 0.71.0， used in Ce separationLa(OH)3 Lu(OH)3AcidityKsp: 109 1024 Precipitation pH: 7.82 6.30 Chloride, sulfate, nitrate: solubleOxalate, carbonate, fluoride, phosphate: low solubilityLnOCl+HCl+5H2OLn2O3+C+Cl2 LnCl3+COLn2O3+NH4Cl LnCl3+NH3+H2OLn2O3+SOCl2 LnCl3+SO2 LnCl36H2O = Ln2(C2O4)3 Ln2O3 +CO+CO2 Salts2