Lanthanum [La] (CAS-ID: 7439-91-0) locate me
An: 57 N: 82 Am: 138.9055 (2)
Group Name: Lanthanoid
Block: f-block  Period: 6 (lanthanoid)
State: solid at 298 K
Colour: silvery white Classification: Metallic
Boiling Point: 3737K (3464'C)
Melting Point: 1193K (920'C)
Density: 6.162g/cm3
Shell Structure diagram | Atomic Radius diagram
Isotopes | More Info
Discovery Information
Who: Carl Mosander
When: 1839
Where: Sweden
Name Origin
Greek: lanthanein (to lie hidden).
Sources
Found with other rare earch elements in monazite and bastnasite.
Uses
Because it gives glass refractive properties, it is used in expensive camera lenses. Also used in lighter flints, studio lighting, battery electrodes and catalytic converters. Lanthanum is silvery white, malleable, ductile, and soft enough to be cut with a knife. It is one of the most reactive of the rare-earth metals. It oxidises rapidly when exposed to air. Cold water attacks lanthanum slowly, and hot water attacks it much more rapidly. The metal reacts directly with elemental carbon, nitrogen, boron, selenium, silicon, phosphorus, sulfur, and with halogens. It is a component of misch metal (used for making lighter flints). Some rare-earth chlorides, such as lanthanum chloride (LaCl3), are known to have anticoagulant properties.
Small amounts of lanthanum added to steel improves its malleability, resistance to impact and ductility; added to iron helps to produce nodular cast iron; added to molybdenum decreases the hardness of this metal and its sensitivity to temperature variations.
Hydrogen sponge alloys can contain lanthanum. These alloys are capable of storing up to 400 times their own volume of hydrogen gas in a reversible adsorption process.
Lanthanum Hexaboride (LaB6) crystals are used in high brightness, extended life, thermionic electron emission sources for scanning electron microscopes.
Notes
Cold water attacks lanthanum slowly, while hot water attacks it much more rapidly.
In animals, the injection of lanthanum solutions produces glycaemia, low blood pressure, degeneration of the spleen and hepatic alterations.
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