Lanthanum

At A Glance: La

Atomic Number: 57
Atomic Symbol: La
Atomic Weight: 138.9055
Electron Configuration: [Xe]6s25d1
Atomic Radius: 240 pm (Van der Waals)
Melting Point: 918 °C
Boiling Point: 3464 °C
Oxidation States: 2
Sources: Found in rare-earth minerals such as cerite, monazite, allanite, and bastnasite. Monazite and bastnasite are principal ores in which lanthanum occurs in percentages up to 25 percent and 38 percent respectively.
Uses:
hybrid vehicle batteries, fluid cracking catalysts, glass polishing, fuel cells.Content provided by Los Alamos National Laboratory. Used with permission.

Rare Earth Element - Lanthanum
Rare Earth Element - Lanthanum
Lanthanum Spin Video

Photos of rare earth elements used on our site are copyright of Max Whitby and Theodore Gray. Used with permission.

Lanthanum, the first member of the Lanthanide series, is recovered from the Bastnasite mineral by solvent extraction. Lanthanum is a strategically important Rare Earth element due to its activity in catalysts needed to create fuel for vehicles and aircraft. Lanthanum also is key to energy providing alloys used everyday in fuel cells and batteries. Should electric vehicles become a staple in the future, they will most likely use Lanthanum-rich, energy-efficient battery materials for power generation. Electric vehicles may one day consume large quantities of Lanthanum for power storage.

The most active petroleum cracking catalysts, that help create fuel needed to run our vehicles, rely on Lanthanum-rich material. These catalysts represent the major use of Lanthanum and are responsible for eliminating leaded gasoline from our environment. The use of these Lanthanide fluidized cracking catalysts also promotes very energy efficient petroleum cracking.

Lanthanum provides optical lens designers with more flexibility than ever before because Lanthanum is the key to modifying glass crystal structure and the refractive index. Advances in the quality of high-tech digital cameras, video cameras, and many other sensitive optical applications would not be possible without Lanthanum or other Rare Earths.

Lanthanum comprises part of the alloy structure that can be used in fuel cells. The alloys can store hydrogen at many times their own volume thus creating efficient energy sources. Lanthanum also provides the classic inter-metallic hydride used in NiMH rechargeable batteries. One of the more common uses of these types of batteries is in laptop computers. Lanthanum nickel alloys have the outstanding hydrogen storage properties needed for longer battery life.

Lanthanum phosphors are used in X-ray films and certain lasers to help reduce the dose of radiation to patients by up to 75%. MRI, CAT, and sonogram imaging presentation techniques depend on Lanthanum or other Lanthanide products.

History

From the Greek word lanthanein, to lie hidden. Mosander in 1839 extracted lanthana from impure cerium nitrate and recognized the new element.

Lanthanum was isolated in relatively pure form in 1923. Iron exchange and solvent extraction techniques have led to much easier isolation of the so-called “rare-earth” elements.

Sources

Lanthanum is found in rare-earth minerals such as cerite, monazite, allanite, and bastnasite. Monazite and bastnasite are principal ores in which lanthanum occurs in percentages up to 25 percent and 38 percent respectively. Misch metal, used in making lighter flints, contains about 25 percent lanthanum.

The availability of lanthanum and other rare earths has improved greatly in recent years. The metal can be produced by reducing the anhydrous fluoride with calcium.

Properties

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 oxidizes rapidly when exposed to air. Cold water attacks lanthanum slowly, while hot water attacks it much more rapidly.

The metal reacts directly with elemental carbon, nitrogen, boron, selenium, silicon, phosphorus, sulfur, and with halogens.

At 310°C, lanthanum changes from a hexagonal to a face-centered cubic structure, and at 865°C it again transforms into a body-centered cubic structure.

Isotopes

Natural lanthanum is a mixture of two stable isotopes, 138La and 139La. Twenty three other radioactive isotopes are recognized.

Sources: Los Alamos National Laboratory; Molycorp

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