Lanthanum Facts - La Element

Chemical & Physical Properties

Lanthanum facts
Lanthanum is atomic number 57.

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Lanthanum is element number 57 with element symbol La. It is a soft, silver-colored, ductile metal known as the starting element for the lanthanide series. It is a rare earth element that usually displays the oxidation number of +3. While lanthanum serves no known biological role in humans and other animals, it is an essential element for some types of bacteria. Here is a collection of La element facts, along with the atomic data for lanthanum.

Fast Facts: Lanthanum

  • Element Name: Lanthanum
  • Element Symbol: La
  • Atomic Number: 57
  • Appearance: Silvery white solid metal
  • Atomic Weight: 138.905
  • Group: Group 3
  • Period: Period 6
  • Block: d-block or f-block
  • Electron Configuration: [Xe] 5d1 6s2

Interesting Lanthanum Facts

  • Lanthanum is a metal so soft it can be cut with a butter knife. It is highly malleable and ductile. Although the freshly cut metal is bright silver, it rapidly oxidizes or tarnishes in air.
  • Lanthanum was discovered by Carl Mosander in 1839 in the mineral cerite. Mosander was a student of Swedish chemist Berzelius, who had discovered cerium in cerite in 1803. Mosander had suspected ceria contained more rare earth elements besides cerium. Axel Erdmann independently discovered lanthanum the same year as Mosander from a Norwegian mineral Erdmann named mosandrite, in honor of Mosander. Pure lanthanum metal was not produced until 1923 by H. Kremers and R. Stevens.
  • Berzelius suggested the named Lanthana for the new element, which comes from the Greek word "lanthano", meaning "to be hidden".
  • Natural lanthanum is a mixture of two isotopes. La-139 is stable, while La-138 is radioactive. At least 38 isotopes of the element have been produced. 
  • Lanthanum is one of the most reactive of the rare earth elements. Its uses are somewhat limited by how readily it oxidizes. It is the strongest base of there found in hybrid cars. About 10 kg of lanthanum are needed to make one Toyota Prius ba trivalent lanthanides.
  • Lanthanum is used in nickel-metal hydride batteries, which attery! Lanthanum compounds may be added to pool produces to lower levels of phosphates, reducing algae growth. Lanthanum is also used as a petroleum cracking catalyst, as a steel additive, to make nodular cast iron, to make infrared absorbing glass and night vision goggles, and to make high-end camera and telescope lenses. Lanthanum oxide has a low dispersion and high refractive index.
  • Lanthanum has no known function in human or animal nutrition. Because it is so reactive, it is considered moderately toxic. Lanthanum carbonate is used to reduce blood phosphate levels in patients with kidney disease.
  • Like most rare earth, lanthanum is not really all that rare, just hard to isolate. Lanthanum is present at an abundance of about 32 parts per million in the Earth's crust.
Lanthanum Element Sample
Lanthanum is a soft, ductile silvery metal. Jurii

Lanthanum Atomic Data

Element Name: Lanthanum

Atomic Number: 57

Symbol: La

Atomic Weight: 138.9055

Discovery: Mosander 1839

Name Origin: From the Greek word lanthaneis (to lie hidden)

Electron Configuration: [Xe] 5d1 6s2

Group: lanthanide

Density @ 293 K: 6.7 g/cm3

Atomic Volume: 20.73 cm3/mol

Melting Point: 1193.2 K

Boiling Point: 3693 K

Heat of Fusion: 6.20 kJ/mol

Heat of Vaporization: 414.0 kJ/mol

1st Ionization Energy: 538.1 kJ/mole

2nd Ionization Energy: 1067 kJ/mole

3rd ionization Energy: 1850 kJ/mole

Electron Affinity: 50 kJ/mole

Electronegativity: 1.1

Specific Heat: 0.19 J/gK

Heat Atomization: 423 kJ/mole atoms

Shells: 2,8,18,18,9,2

Minimum Oxidation Number: 0

Maximum Oxidation Number: 3

Structure: hexagonal

Color: silvery-white

Uses: lighter flints, camera lenses, cathode ray tubes

Hardness: soft, malleable, ductile

Isotopes (half-life): Natural lanthanum is a mix of two isotopes, though more isotopes now exist. La-134 (6.5 minutes), La-137 (6000.0 years), La-138 (1.05E10 years), La-139 (stable), La-140 (1.67 days), La-141 (3.9 hours), La-142 (1.54 minutes)

Atomic Radius: 187 pm

Ionic Radius (3+ ion): 117.2 pm

Thermal Conductivity: 13.4 J/m-sec-deg

Electrical Conductivity: 14.2 1/mohm-cm

Polarizability: 31.1 A^3

Source: monazite (phosphate), bastnaesite


  • Emsley, John (2011). Nature's building blocks: An A-Z Guide to the Elements. Oxford University Press. ISBN 978-0-19-960563-7.
  • Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
  • Hammond, C. R. (2004). The Elements, in Handbook of Chemistry and Physics (81st ed.). CRC press. ISBN 978-0-8493-0485-9.
  • Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. ISBN 0-8493-0464-4.
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Your Citation
Helmenstine, Anne Marie, Ph.D. "Lanthanum Facts - La Element." ThoughtCo, Aug. 28, 2020, Helmenstine, Anne Marie, Ph.D. (2020, August 28). Lanthanum Facts - La Element. Retrieved from Helmenstine, Anne Marie, Ph.D. "Lanthanum Facts - La Element." ThoughtCo. (accessed May 30, 2023).