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The lanthanide (/ ˈ l æ n θ ə n aɪ d /) or lanthanoid (/ ˈ l æ n θ ə n ɔɪ d /) series of chemical elements [a] comprises at least the 14 metallic chemical elements with atomic numbers 57–70, from lanthanum through ytterbium. In the periodic table, they fill the 4f orbitals.
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 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 separation of neodymium and praseodymium was a particularly difficult one, and those were formerly thought to be just one element didymium – but that is an alloy of the two. [ citation needed ] There are two series of rare-earth metals , the lanthanides and the actinides, both of whose families all have very similar chemical and physical ...
In this way selective stripping of the lanthanides can be used to make a separation of a mixture of the lanthanides into mixtures containing fewer lanthanides. Under ideal conditions this can be used to obtain a single lanthanide from a mixture of many lanthanides.
A separatory funnel used for liquid–liquid extraction, as evident by the two immiscible liquids.. Liquid–liquid extraction, also known as solvent extraction and partitioning, is a method to separate compounds or metal complexes, based on their relative solubilities in two different immiscible liquids, usually water (polar) and an organic solvent (non-polar).
Lanthanide chlorides are a group of chemical compounds that can form between a lanthanide element (from lanthanum to lutetium) and chlorine. The lanthanides in these compounds are usually in the +2 and +3 oxidation states , although compounds with lanthanides in lower oxidation states exist.
General chemical structure of a lanthanocene. A lanthanocene is a type of metallocene compound that contains an element from the lanthanide series. The most common lanthanocene complexes contain two cyclopentadienyl anions and an X type ligand, usually hydride or alkyl ligand.