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Lanthanide and actinide aqua ions have higher solvation numbers (often 8 to 9), with the highest known being 11 for Ac 3+. The strength of the bonds between the metal ion and water molecules in the primary solvation shell increases with the electrical charge, z, on the metal ion and decreases as its ionic radius, r, increases. Aqua ions are ...
Lanthanide metals react exothermically with hydrogen to form LnH 2, dihydrides. [1] With the exception of Eu and Yb, which resemble the Ba and Ca hydrides (non-conducting, transparent salt-like compounds),they form black pyrophoric, conducting compounds [6] where the metal sub-lattice is face centred cubic and the H atoms occupy tetrahedral sites. [1]
The lighter/larger lanthanides adopt a hexagonal 7-coordinate structure while the heavier/smaller ones adopt a cubic 6-coordinate "C-M 2 O 3" structure. [50] All of the sesquioxides are basic, and absorb water and carbon dioxide from air to form carbonates, hydroxides and hydroxycarbonates. [ 57 ]
About 40-50% of the actinide contraction has been attributed to relativistic effects. [2] A decrease in atomic radii can be observed across the 5f elements from atomic number 89, actinium, to 102, nobelium. This results in smaller than otherwise expected atomic radii and ionic radii for the subsequent d-block elements starting with 103, lawrencium.
Actinide salts can also be obtained by dissolving the corresponding hydroxides in acids. Nitrates, chlorides, sulfates and perchlorates of actinides are water-soluble. When crystallizing from aqueous solutions, these salts form hydrates, such as Th(NO 3) 4 ·6H 2 O, Th(SO 4) 2 ·9H 2 O and Pu 2 (SO 4) 3 ·7H 2 O. Salts of high-valence actinides ...
Organolanthanide chemistry is the field of chemistry that studies organolanthanides, compounds with a lanthanide-carbon bond. Organolanthanide compounds are different from their organotransition metal analogues in the following ways: They are far more air- and water-sensitive and are often pyrophoric.
Plutonium is a transuranic radioactive chemical element, an actinide metal. Actinide chemistry (or actinoid chemistry) is one of the main branches of nuclear chemistry that investigates the processes and molecular systems of the actinides. The actinides derive their name from the group 3 element actinium.
The actinide concept explained some of the observed properties of the first few actinides, namely the presence of +4 to +6 oxidation states, and proposed hybridization of the 5f and 6d orbitals, whose electrons were shown to be loosely bound in these elements. It also supported experimental results for a trend towards +3 oxidation states in the ...