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Lanthanum is traditionally counted among the rare earth elements. Like most other rare earth elements, its usual oxidation state is +3, although some compounds are known with an oxidation state of +2. Lanthanum has no biological role in humans but is used by some bacteria.
Lanthanum(III) oxide, also known as lanthana, chemical formula La 2 O 3, is an inorganic compound containing the rare earth element lanthanum and oxygen. It is used in some ferroelectric materials, as a component of optical materials, and is a feedstock for certain catalysts, among other uses.
The oxidation states are also maintained in articles of the elements (of course), and systematically in the table {{Infobox element/symbol-to-oxidation-state}} See also [ edit ]
The oxidation states are also very stable; with the exceptions of SmI 2 [27] and cerium(IV) salts, [28] lanthanides are not used for redox chemistry. 4f electrons have a high probability of being found close to the nucleus and are thus strongly affected as the nuclear charge increases across the series; this results in a corresponding decrease ...
Lanthanum manganite is an inorganic compound with the formula LaMnO 3, ... In lanthanum manganite, both the La and the Mn are in the +3 oxidation state.
The salt-like dihalides include those of Eu, Dy, Tm, and Yb. The formation of a relatively stable +2 oxidation state for Eu and Yb is usually explained by the stability (exchange energy) of half filled (f 7) and fully filled f 14. GdI 2 possesses the layered MoS 2 structure, is ferromagnetic and exhibits colossal magnetoresistance. [10]
LaC 2 reacts with water to form acetylene, C 2 H 2 and a mixture of complex hydrocarbons. [3] LaC 2 is a metallic conductor, in contrast to CaC 2 which is an insulator. [3] The crystal structure of LaC 2 shows that it contains C 2 units with a C-C bond length of 130.3 pm, which is longer than the C-C bond length in calcium carbide, 119.2 pm, which is close to that of ethyne. [3]
Praseodymium can form many different oxides, although the only oxides that are stable at room temperature are Pr 2 O 3, Pr 6 O 11 and PrO 2.Praseodymium(III) oxide is a green powder that forms hexagonal crystals, [14] and crystallizes in the manganese(III) oxide or bixbyite structure. [15]