Trivalent gadolinium

Trivalent gadolinium with f7 configuration has isotropic distribution of electrons and hence cannot produce pseudo contact shift. However, when the Lewis acid-base interaction is partly covalent, the unpaired electron spin density influences the molecular framework of the base and causes an LIS known as contact shift. Gd(III) is used to ascertain the contributions of contact shift to the measured LIS. 

As the ligand phosphorescence is, in general, completely quenched at room temperature, for these coordination compounds , it is necessary to record the spectra at low temperature (77 K), otherwise the T states are deactivated by non-radiative processes. In this case, trivalent gadolinium complexes are generally used due to the intrinsic spectroscopic characteristics of the Gd + ion (Figure 2). 

The magnetic moment of trivalent gadolinium (Z = 64) complexes can be obtained by spin only formula but not for trivalent terbium complexes reason ... 

Lanthanide ions offer narrow EPR line widths, and the first successful device (Scovil et al. 1957) made use of three levels of the trivalent gadolinium ion, 87/2, in lanthanum ethylsulphate. A 90 mg single crystal containing 0.5%Gd, and 0.2% Ce to obtain suitable spin-lattice relaxation rates (Feher and Scovil 1957), was... 

Gd (4f ). Trivalent gadolinium ions only absorb UV radiation with an energy greater than 32 000 cm (wavelengths smaller than 311 nm). Gd is colorless in solutions and single crystals, powders are white. 

Bivalence is similarly shown for europium, and trivalence for the elements gadolinium to thulium. 

Most properties are similar to the rare-earth analog gadolinium that has If electrons. The trivalent oxidation state (Cm3+) is most stable. The metal is reactive, being more electropositive than aluminum. 

The importance of this system for the separation of the trivalent species from each other was recognized in 1953 by D. F. Peppard and his collaborators at the Argonne National Laboratory. This was followed in the same year by the isolation of the "first kilogram" of pure gadolinium by B. Weaver and his co-workers at the Oak Ridge National Laboratory using the same method. Subsequently, the method has been used on both a laboratory and a commercial scale. 

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