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The electronic configuration of most neutral gas-phase lanthanide atoms is [Xe]6s 2 4f n, where n is 56 less than the atomic number Z. Exceptions are La, Ce, Gd, and Lu, which have 4f n −1 5d 1 (though even then 4f n is a low-lying excited state for La, Ce, and Gd; for Lu, the 4f shell is already full, and the fifteenth electron has no choice ...
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]
Among the lanthanides, lanthanum is exceptional as it has no 4f electrons as a single gas-phase atom. Thus it is only very weakly paramagnetic, unlike the strongly paramagnetic later lanthanides (with the exceptions of the last two, ytterbium and lutetium, where the 4f shell is completely full). [20]
The lanthanide ions in these complexes can readily react with oxygen and water, leading to oxidation or hydrolysis, which damages the material’s structure and reduces its efficiency. This makes handling and storage difficult, requiring protective environments like sealed containers or inert gas atmospheres.
The element's atomic radius is the second largest among all the lanthanides but is only slightly greater than those of the neighboring elements. [6] It is the most notable exception to the general trend of the contraction of lanthanide atoms with the increase of their atomic numbers (lanthanide contraction [7]). Many properties of promethium ...
Gas phase ion chemistry is a field of science encompassed within both chemistry and physics. It is the science that studies ions and molecules in the gas phase, most often enabled by some form of mass spectrometry. By far the most important applications for this science is in studying the thermodynamics and kinetics of reactions.
Most lanthanides can use only three electrons as valence electrons, as afterwards the remaining 4f electrons are too strongly bound: cerium is an exception because of the stability of the empty f-shell in Ce 4+ and the fact that it comes very early in the lanthanide series, where the nuclear charge is still low enough until neodymium to allow ...
La 2 O 3 powder. Lanthanum oxide is a white solid that is insoluble in water, but dissolves in acidic solutions. La 2 O 3 absorbs moisture from air, converting to lanthanum hydroxide. [2]