Europium complexes hydrated ions

The preparation of europium metasilicate hydrate from solutions of europium bromide and sodium metasilicate has been described.The kinetics and mechanism of the reduction of thiocyanato- and isothiocyanato-penta-amminecobalt(iii) ions by europium(ii) in acid solution have been discussed in terms of europium(ii) attack on the ambidentate bridging ligand at the end remote from the cobalt centre. The differences in the activation enthalpies for the reduction of the complexes were attributed to (a) differences in enthalpy of formation of the precursor complex Eu - X - Co (NH3)5, and (b) ease of stretching of the Co—S or Co—N bond in the precursor complex. The low-temperature Mossbauer spectrum of EUH2 suggested the covalent transfer of electron density. to the metal 6s orbital to be more marked in EuH2 than EuO. ... 

Escherichia coli nitrate reductase structure, 1438 Europium complexes -diketones, 1081 dipositive oxidation state hydrated ions, 1109... 

Edta-related lanthanide complexes are of course coordinatively unsaturated in the absence of other ligands. In water, they are hydrated and the water of hydration may be displaced by other species. The kinetics of such a process, the reaction of europium 1,2-diaminocyclohexane-tetraacetate, [Eu(dcta)aq] with iminodiacetate ion, ida , to give [Eu(dcta)(ida)] ", have been studied by the elegant method of selective tunable laser excitation of the transition in... 

---