The lanthanides and yttrium

Solvates of the monohydroxylic alcohols have been extensively studied. The expected pattern of more solvent molecules per chloride molecule is reported for the lanthanide and yttrium trichlorides. For scandium trichloride, the existence of ScCl3-2EtOH and ScCl3-2C6H13OH compares unexpectedly with the tris-alcoholates reported for the n-C6... 

Antipyrine (l,5-dimethyl-2-Phenyl-3-Pyrazolone) is known to form hexakis complexes with the lanthanides and yttrium salts 38). The bright green fluores-... 

The values of the first four ionization energies for the lanthanides (and yttrium) are listed in Table 2.2. 

In weakly acidic media the lanthanides and yttrium react with Arsenazo III (formula 4.10) to form coloured complexes which are the basis of the sensitive method for determining the total of REE or any element from this group [48-51]. In weakly acidic solution, the reagent is violet, and its complexes with the rare-earth elements are green. The maximum absorbance for Ce(III) is obtained at pH 2.3-2.7. The optimum pH values for the various REE differ slightly. 

Scandium (Sc, at. mass 44.96) occurs in its compounds exclusively in the III oxidation state. Some of its chemical properties resemble those of the lanthanides and yttrium. Scandium hydroxide Sc(OH>3 precipitates at a pH as low as 4.8 and dissolves in alkaline medium in this respect scandium resembles aluminium. 

Fleischer M, Altschuler ZS (1986) The lanthanides and yttrium in minerals of the apatite group - an analysis of the available data. N Jahrb Mineral Monatsh 467-480 Fleischer M, Mandarine JA (1995) Glossary of Mineral Species (7th ed). Mineral Record, Tucson, Arizona. Fortsch E, Freiburg IB (1970) Untersuchungen as mineralien der pyromorphit grappe. N Jahib Mineral Abh 113 219-250... 

Fold angles for complexes of the lanthanides and yttrium with ligand I. 

The most common gravimetric method for the determination of the lanthanides and yttrium is the precipitation of the oxalates followed by ignition at 800°C or higher to the oxides, R2O3. Pr and Tb form the oxides PreOn and Tb407 under these conditions and Ce is oxidized to Ce02 at temperatures over 350 C. 

GEOCHEMISTRY AND MINERALOGY OF THE RARE EARTHS 2. Formation and abundances of the lanthanides and yttrium... 

Concentrations of the lanthanides and yttrium in a composite of nine chondrites (Haskin et al., 1968) are given in table 21.1. 

To what extent are the lanthanides and yttrium from different sources mixed... 

Because the lanthanides and yttrium are dispersed elements they are found mainly as trace constituents of common rocks. Within those rocks they occur partly as trace constituents of the major, rock-forming minerals and partly in accessory minerals in which the lanthanides are either essential constituents (e.g., monazite) or are concentrated (e.g., apatite). More than 100 different lanthanide and lanthanide-concentrating minerals are known. Most of these form from liquids that are highly differentiated chemically relative to common magmas. Such liquids are rich in a wide variety of elements that are trace elements in terms of their natural abundances but major constituents of the final dregs of liquid when magmas freeze. 

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