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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.
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 ...
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 structure can be described by slightly distorted YbO 6 octahedra tilted in the a−b+a− configuration according to Glazer's notation and antiparallel displaced La 3+ ions. The rotation of the YbO 6 octahedra reduces the coordination number of the La from 12 to 8. It exhibits exhibit a negative thermal expansion along the a and b axes.
Lanthanum(III) iodate can be obtained by reacting a La 3+ salt with potassium iodate or ammonium iodate and precipitating it: [1] La 3+ + 3 IO 3 − → La(IO 3 ) 3 ↓ Properties
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 ...
Lanthanum barium copper oxide, or LBCO, is an inorganic compound with the formula CuBa 0.15 La 1.85 O 4. It is a black solid produced by heating an intimate mixture of barium oxide, copper(II) oxide, and lanthanum oxide in the presence of oxygen. The material was discovered in 1986 and was the first high temperature superconductor. [1]