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The boron rich borides are typical of the lanthanides (and groups 1–3) whereas for the transition metals tend to form metal rich, "lower" borides. [76] The lanthanide borides are typically grouped together with the group 3 metals with which they share many similarities of reactivity, stoichiometry and structure.
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 principal use of lanthanum hexaboride is in hot cathodes, either as a single crystal or as a coating deposited by physical vapor deposition.Hexaborides, such as lanthanum hexaboride (LaB 6) and cerium hexaboride (CeB 6), have low work functions, around 2.5 eV.
The main group metals, lanthanides and actinides form a wide variety of boron-rich borides, with metal:boron ratios up to YB 66. The properties of this group vary from one compound to the next, and include examples of compounds that are semi conductors, superconductors, diamagnetic, paramagnetic, ferromagnetic or anti-ferromagnetic. [1]
The lanthanides are the 15 rare-earth chemical elements which lie between lanthanum and lutetium on the periodic table. The lanthanides are trivalent metals . Subcategories
L. Lanthanide trichloride; Lanthanum acetate; Lanthanum acetylacetonate; Lanthanum aluminate; Lanthanum barium copper oxide; Lanthanum carbide; Lanthanum carbonate
Erbium tetraboride is a boride of the lanthanide metal erbium. [2] It is hard and has a high melting point. Industrial applications of erbium boride include use in semiconductors, the blades of gas turbines, and the nozzles of rocket engines. [3]
Contrary to cyclopentadienides of most other lanthanides, in Sm(C 5 H 5) 3 some C 5 H 5 rings bridge each other by forming ring vertexes η 1 or edges η 2 toward another neighboring samarium, thus creating polymeric chains. [24] The chloroderivative Sm(C 5 H 5) 2 Cl has a dimer structure, which is more accurately expressed as (η(5)−C 5 H 5 ...