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Lanthanum is a chemical element with the symbol La and the atomic number 57. It is a soft, ductile, silvery-white metal that tarnishes slowly when exposed to air. 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.
The rare-earth elements (REE), also called the rare-earth metals or rare earths, and sometimes the lanthanides or lanthanoids (although scandium and yttrium, which do not belong to this series, are usually included as rare earths), [1] are a set of 17 nearly indistinguishable lustrous silvery-white soft heavy metals.
Naturally occurring lanthanum (57 La) is composed of one stable (139 La) and one radioactive (138 La) isotope, with the stable isotope, 139 La, being the most abundant (99.91% natural abundance). There are 39 radioisotopes that have been characterized, with the most stable being 138 La, with a half-life of 1.03×10 11 years; 137 La, with a half ...
The first lanthanum C 60 complex called La@C 60 was synthesized in 1985. [2] The @ in the name reflects the notion of a small molecule trapped inside a shell. Two types of endohedral complexes exist: endohedral metallofullerenes and non-metal doped fullerenes.
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.
Lanthanum(III) sulfate is an inorganic compound with the formula La 2 (SO 4) 3 ·xH 2 O (0 ≥ x ≥ 9). It forms various hydrates, the most common one being the nonahydrate, which are all white solids.
The strontium (valence 2+) doping on lanthanum (valence 3+) introduces extra holes in the valence band and thus increases electronic conductivity. Depending on the x value in La 1−x Sr x MnO 3, the unit cell of LSMO can be rhombohedral, cubic, or hexagonal. This change in the unit cell is explained on the basis of the Goldschmidt tolerance ...
Lanthanum(III) sulfide can be prepared from the effect of sulfur vapor on metallic lanthanum: 2 La + 3 S → La 2 S 3. It can also be prepared from the effect of hydrogen sulfide on lanthanum: 2 La + 3H 2 S → La 2 S 3 + 3 H 2. The effect of hydrogen sulfide on lanthanum oxide in the presence of reducing agents also produces lanthanum(III ...