Lanthanum

iso	NA	half-life	DT	DE (MeV)	DP
¹³⁷La	syn	60,000 yrs	ε	0.600	¹³⁷Ba
¹³⁸La	0.09%	1.05x10¹¹ yrs	ε	1.737	¹³⁸Ba
¹³⁸La	.09%	1.05x10¹¹ yrs	β−	1.044	¹³⁸Ce
¹³⁹La	99.91%	¹³⁹La is stable with 82 neutrons.

All properties are for STP unless otherwise stated.

Lanthanum is an abundant but a rare earth metal that has many interesting character traits and uses. It is soft, silvery, malleable and a white metal which has sharp crystalline structures at room temperature. Since Lanthanum is very easily oxidized, it is an element only used for research purposes. Monazite, and bastnäsite, are the ores in which lanthanum is found. Before 1949, bastnäsite was rare to find and only the monazite was used for commercial purposes to find Lanthanum.

Also lanthanum is one of the rare chemicals that can be found in houses with items such as color televisions, energy saving lamps, glasses and fluorescent lamps. The use of lanthanum is still growing due to the fact that it produces catalysers and used to polish glass. Discovered by, Carl Auer von Welsbach, the first use of lanthanum was in gas lantern mantles. The nickel metal hydride batteries are used in hybrid cars batteries like the Toyota Prius. In the 1870s Dmitri Mendeleev used it to separate the less soluble lanthanum from the more soluble didymium.

Properties

solid lanthanum

Lanthanum is soft, silvery, malleable and a white metal which has sharp crystal structures at room temperature. When exposed to moisture in air at a room temperature, it forms a hydrated oxide with a significant volume increase. The metal reacts directly with an elemental carbon, nitrogen, selenium, boron, silicon, sulphur, and with halogens. Lanthanum is electropositive and reacts slowly with cold water and quickly with hot water to form a lanthanum hydroxide. Since Lanthanum is easily oxidized, it is a element only used for research purposes. When Lanthanum atoms have been isolated by putting them into fullerene molecules, the carbon nanotubes are filled with the lanthanum encapsulated fullerenes. At 865 C lanthanum turns into a body centered cubic structure and at 310 C lanthanum changes to a face centered cubic structure.[1]

Occurrences

Lanthanum is in the group of rare earth metals, which is uncommon elements, for example lanthanum is not as common as lime or magnesia, and has been known to only be found in a few deposits. Monazite , and bastnäsite, are the ores in which lanthanum is found. Lanthanum is found in percentages of up to 25 to 38 percent of the monazite , and bastnäsite ores. Before 1949, bastnäsite was very rare to find and only monazite was used in commercial purposes to find Lanthanum. Later in that year, There was a huge deposit found at Mountain Pass, California. This discovery made geologists aware to the existence of a whole new rare earth deposit. There is a rare earth holding carbonatite, other example of one that was soon discovered is particularly in Africa and China. Also lanthanum is one of the rare chemicals that can be found in houses with equipment such as color televisions, energy saving lamps, glasses and fluorescent lamps. When you add lanthanum in small amounts it improves the malleability and the resistance of steel. Lanthanum salts are included in the zeolite catalysts that are used in petroleum refining because they stabilize the zeolite at high temperatures. Even though it is one of the more abundant rare earth elements, lanthanum can rarely be found in nature as it occurs in very small amounts. The world production of lanthanum oxide is in around 12,000 tonnes per year, and there are currently reserves of lanthanum are around 6 million tonnes, but the use of lanthanum is still growing due to the fact that it is produces catalysers and used to polish glass.[2]

Uses

toyota prius

The first discovered by Carl Auer von Welsbach, the first use of lanthanum was in gas lantern mantles. Called a Actinophor, it was a mixture of 60 percent magnesium oxide, 20 percent lanthanum oxide and 20 percent yttrium oxide. Another, more modern use for Lanthanum is nickel metal hydride batteries. A typical hybrid car battery for a Toyota Prius uses 10 to 15 kg of lanthanum. In fact most of the hybrid cars use nickel metal hydride batteries where large quantities of lanthanum is used for the production of hybrid automobiles. Due to gas consumption, engineers may start to push the technology to increase fuel mileage, which would be twice the amount of lanthanum could be required per car. Storing up to 400 times their own volume of hydrogen gas in a reversible adsorption process, hydrogen sponge alloys can contain some lanthanum. Used for studio lighting and projection, carbon lighting applications is especially used by the motion picture industry. Putting in small amounts of lanthanum in steel improves its malleability, resistance to impact and ductility, while any additions of lanthanum to molybdenum weakens its hardness and sensitivity to temperature changes. Small amounts when added are used to produce nodular cast iron.[3]

History

In 1839, Mosander extracted a new earth lanthana from a impure cerium nitrate and recognized the new element. Also lanthanum was isolated in its pure form in 1923. The iron exchange and the solvent extraction techniques have led to a much easier isolation of the rare earth elements. Discovered by Swedish chemist Carl Gustav Mosander 1839, Lanthanum was decomposed, by heating and treating the resulting salt with a nitric acid, as a sample of cerium nitrate. The most strongly basic of all the trivalent lanthanoids, Lanthanumm is what allowed Mosander to isolate and purify the salts of this element. Invented by Dmitri Mendeleev, the alternative technique of fractional crystallization was in the form of double ammonium nitrate tetrahydrate. He also used it to separate the less soluble lanthanum from the more soluble didymium somewhere in the 1870s. Started in the late 1950s, the system that Dmitri Mendeleev discovered, would be used commercially in the process of lanthanum purification until the development of a practical solvent extraction method. Carl Auer von Welsbach discovered the splitting of didymium, nitric acid and was used as a solvent to lower the solubility of the system. Also since it has only one lanthanoid/cerium, which itself is usually removed due to its potential tetravalency, lanthanum is basically easy to purify. [4]

References

Lanthanum: the essentials by Mark Winter. The University of Sheffield and WebElements Ltd, UK.
Lanthanum by Steve Gagnon. Jefferson labs. Accessed 22 May 2010.
Lanthanum Honeywell International Inc. Corrosion Portal. Accessed 22 May 2010
Lanthanum Wikipedia. Accessed 22 May 2010.
Lanthanum Lenntech Water Treatment Solutions. Accessed 22 May 2010.
4 Rare Earth Elements That Will Only Get More Important by Maggie Koerth-Baker. Popular Mechanics magazine. Accessed 22 May 2010.

Lanthanum

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