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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 ...
It is the eponym of the lanthanide series, a group of 15 similar elements between lanthanum and lutetium in the periodic table, of which lanthanum is the first and the prototype. Lanthanum is traditionally counted among the rare earth elements .
The lanthanite crystal structure consists of layers of 10-fold coordinated REE-oxygen (O) polyhedra and carbonate (CO 3 2−) groups connected by hydrogen bonds to interlayer water molecules, forming a highly hydrated structure. [8]
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 rare-earth elements patterns observed in igneous rocks are primarily a function of the chemistry of the source where the rock came from, as well as the fractionation history the rock has undergone. [27] Fractionation is in turn a function of the partition coefficients of each element. Partition coefficients are responsible for the ...
Cerium(IV) oxide ("ceria") has the fluorite structure, similarly to the dioxides of praseodymium and terbium.Ceria is a nonstoichiometric compound, meaning that the real formula is CeO 2−x, where x is about 0.2.
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]
It is a metal, the fourteenth and penultimate element in the lanthanide series, which is the basis of the relative stability of its +2 oxidation state. Like the other lanthanides, its most common oxidation state is +3, as in its oxide , halides , and other compounds.