Bi3+(aq) ‹ Bi(III) E0 ~ +2 V compounds often have stereochemically active lone pairs Factors favoring distorted geometries ‹ Low coordination numbers favor a stereochemically active lone pair – BiF3 and SnCl3- ‹ Lighter elements show a stronger tendency than their heavier relatives to be distorted – Sb > Bi ‹ Small ligands favor the presence of a distortion – F and alkoxides rather than I Lanthanide chemistry ‹ The lanthanides are technologically important ‹ Their chemistry is simple – dominated by the +3 oxidation state – the M3+ ions are hard Overview of lanthanide properties Applications of lanthanides ‹ They are widely used in ceramics synthesis – High Tc superconductors – Conducting oxide electrodes ‹ They are used in phosphors for devices such as TV sets ‹ They are used in lasers – Nd-YAG Compare oxidation states of the lanthanides and actinides The lanthanide contraction Separations ‹ Lanthanide ions are difficult to fully separate from one another using conventional chemical means as there sizes and charges are so similar – Can separate elements that readily do to +2 or +4 ‹ ‹ Liquid-liquid extraction used for large scale separation Ion exchange chromatography used when high purity is needed Complexes ‹ ‹ ‹ The lanthanides cations are all hard and form complexes with hard donor ligands The complexes often have high coordination numbers 6-10 and irregular geometries Ligands interact very weakly with the f-electons – Crystal field splitting is extremely small and often negligible ‹ Complexes have some applications including NMR shift reagents O O (CH3)3C CF2CF2CF3 fod Actinide chemistry ‹ Much more complicated than that of the rare earths ‹ The early actinides can attain a variety of oxidation states Overview of actinide properties Applications of actinide chemistry ‹ Nuclear fuel/ weapons material processing ‹ Nuclear fuel reprocessing ‹ Nuclear waste remediation Stable oxidation states of actinides Aqueous solution chemistry of the actinides ‹ The formation of oxo species is commonplace ‹ UO22+, UO2+ ‹ PuO22+, PuO2+ ‹ The nature of species present in solution is strongly dependent upon both pH and reduction potential Fission ‹ In a conventional nuclear reactor 235U nuclei capture neutrons.

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Chemistry Explosives Overview Of Metal Chemistry by Angus Paul Wilkinson

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