Discovery Information
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Who: Carl Mosander |
When: 1839 |
Where: Sweden |
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Name Origin
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Greek: lanthanein (to lie hidden). |
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Sources
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Found with other rare earch elements in monazite and bastnasite. |
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Uses
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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.
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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.
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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.
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Lanthanum Hexaboride (LaB6) crystals are used in high brightness, extended life, thermionic electron emission sources for scanning electron microscopes.
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Notes
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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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