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About Lanthanum

Lanthanum Bohr

Swedish chemist Carl Gustav Mosander discovered lanthanum during experiments on an impure sample of cerium nitrate in 1839.

Like most of the rare-earth elements, lanthanum is used in small amounts to alter key properties of other materials. Lanthanum oxide is added to glass to impart increased resistance to alkalis, strength, a high refractive index and low dispersion, and can be used to make infrared-absorbing glass. Lanthanum is also an essential component of ZBLAN glass, which exhibits superior transmittance of infrared light and is used in fiber-optic communication systems. These glasses are used in specialized optical applications such as telescope lenses. Lanthanum-doped ceramic materials are used as both anodes and cathodes in solid oxide fuel cells. Adding small quantities of lanthanum to steel improves its malleability, ductility, and resistance to impact, while the addition of lanthanum to molybdenum decreases its hardness and sensitivity to variations in temperature.

Many rare earth compounds have the ability to produce light in response to absorbing energy from an external source. The first commercial use of lanthanum exploited this property for the production of gas lantern mantles, but unfortunately those mantles produced green-tinged light and were not very successful. Their creator Carl Auer von Welsbach found more success with a cerium-containing mantle several years later. Lanthanum is also a component of mischmetal, an alloy used for lighter flints. Today, lanthanum phosphors like lanthanum fluoride are used in fluorescent lamps, and cerium-doped lanthanum bromide and chloride scintillators serve as radiation detectors by producing light when they absorb ionizing radiation.

Some other properties of lanthanum are exploited in a variety of applications. Many lanthanum compounds can be induced to emit electrons when treated with heat in a process called thermionic emission. Lanthanum boride crystals are used as electron emission sources for electron microscopes and ion thrusters used in space craft. The thermionic emission of electrons of lanthanum compounds is also exploited in carbon arc lamps, in which lanthanum compounds are sometimes components of one of the electrodes. Lanthanum also binds phosphates in solution. Some water treatment products use this property to remove the free phosphates that feed algae, while the drug lanthanum carbonate uses it to absorb excess phosphate in the blood of patients in end-stage kidney failure. Lanthanum catalysts are widely used in the industrial process of refining petroleum for fuel. Additionally, lanthanum catalysts are being investigated for use in many other processes, including photocatalytic hydrogen production and production of syngas from methane.

Lanthanum is often a component of hydrogen sponge alloys--metals that can absorb and store up to 400 times their own volume of hydrogen gas. These alloys are most commonly used as the negative electrode of nickel-metal hydride (NiMH) batteries. NiMH batteries are rechargeable batteries with high storage capacity and are important for the development of green technologies such as electric vehicles.

Many lanthanum-containing thin film compositions have been investigated in the search for high-k gate dielectrics for use in integrated circuits. Silicon dioxide gate dielectrics have been standard for decades, but the industry has reached the limit of thinness for silicon layers that can serve as an effective gate, and the development of alternate materials could theoretically allow for further miniaturization of microelectronics.

Lanthanum is a light rare earth most commonly obtained by processing the rare earth minerals monazite and bastnasite.

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Elemental Lanthanum Lanthanum-rich lanthanide compositions have been used extensively for cracking reactions in FCC catalysts, especially to manufacture low-octane fuel for heavy crude oil. It is utilized in green phosphors based on the aluminate (La0.4Ce0.45Tb0.15)PO4. Lanthanide zirconates and lanthanum strontium manganites are used for their catalytic and conductivity properties and lanthanum stabilized zirconia has useful electrical and mechanical properties. Lanthanum's ability to bind with phosphates in water creates numerous uses in water treatment. It is utilized in laser crystals based on the yttrium-lanthanum-fluoride (YLF) composition. Lanthanum metal is predominantly used in the production of mischmetal and steel additives, but is alsoHigh Purity (99.999%) Lanthanum Oxide (La2O3) Powder important in the production of hydrogen storage alloys for nickel-metal hydride (NiMH) batteries. High Purity (99.999%) Lanthanum (La) Sputtering TargetLanthanum is available as metal and compound forms with purities ranging from 99% to 99.999% (ACS grade to ultra-high purity). Elemental or metallic forms include pellets, rod, wire and granules for evaporation source material purposes. Lanthanum oxides are available in powder and dense pellet form for such uses as optical coating and thin film applications. Oxides tend to be insoluble. Fluorides are another insoluble form for uses in which oxygen is undesirable such as metallurgy, chemical and physical vapor deposition and in some optical coatings. Lanthanum is also available in soluble forms including chlorides, nitrates and acetates. These compounds can be manufactured as solutions at specified stoichiometries.

Lanthanum Properties

Lanthanum (La) atomic and molecular weight, atomic number and elemental symbolLanthanum is a Block F, Group 3, Period 6 element. The number of electrons in each of lanthanum's shells is 2, 8, 18, 18, 9, 2 and its electron configuration is [Xe] 5d1 6s2. The lanthanum atom has a radius of and its Van der Waals radius is Lanthanum Bohr ModelIn its elemental form, CAS 7439-91-0, lanthanum has a silvery white appearance. Lanthanum is the first element in the rare earth or lanthanide series. It is the model for all the other trivalent rare earths and it is the second most abundant of the rare earths after cerium. Lanthanum is found in monazite and bastnasite. Lanthanum was first discovered by Carl Mosander in 1839. The name lanthanum originates from the Greek word Lanthaneia which means 'to lie hidden'.

Symbol: La
Atomic Number: 57
Atomic Weight: 138.9055
Element Category: lanthanide
Group, Period, Block: n/a, 6, f
Color: silvery white
Other Names: Lanthane, Lantanio, Lantânio
Melting Point: 920°C, 1688°F, 1193.15 K
Boiling Point: 3464°C, 6267.2°F, 3737.15 K
Density: 6174 kg·m3
Liquid Density @ Melting Point: 5.94 g·cm3
Density @ 20°C: 6.16 g/cm3
Density of Solid:  6146 kg·m3
Specific Heat: 0.195 kJ/kg K
Superconductivity Temperature: 6.00 [or -267 °C (-449 °F)] K
Triple Point: N/A
Critical Point: N/A
Heat of Fusion (kJ·mol-1): 10.04
Heat of Vaporization (kJ·mol-1): 402.1
Heat of Atomization (kJ·mol-1): 431.29
Thermal Conductivity: 0.134 W/cm/K @ 298.2 K
Thermal Expansion: (r.t.) (poly) 12.1 µm/(m·K)
Electrical Resistivity: 5.70 µΩ-cm @ 25°C
Tensile Strength: N/A
Molar Heat Capacity: 27.11 J·mol-1·K-1
Young's Modulus: (? form) 36.6 GPa
Shear Modulus: (? form) 14.3 GPa
Bulk Modulus: (? form) 27.9 GPa
Poisson Ratio: (? form) 0.280
Mohs Hardness: 2.5
Vickers Hardness: 491 MPa
Brinell Hardness: 363 MPa
Speed of Sound: (20 °C) 2475 m·s?1-1
Pauling Electronegativity: 1.1
Sanderson Electronegativity: N/A
Allred Rochow Electronegativity: 1.08
Mulliken-Jaffe Electronegativity: N/A
Allen Electronegativity: N/A
Pauling Electropositivity: 2.9
Reflectivity (%): N/A
Refractive Index: N/A
Electrons: 57
Protons: 57
Neutrons: 82
Electron Configuration: [Xe] 5d1 6s2
Atomic Radius: 187 pm
Atomic Radius,
non-bonded (Å):
Covalent Radius: 207±8 pm
Covalent Radius (Å): 1.94
Van der Waals Radius: 240 pm
Oxidation States: 3, 2 (strongly basic oxide)
Phase: Solid
Crystal Structure: Hexagonal
Magnetic Ordering: paramagnetic
Electron Affinity (kJ·mol-1) 45.332
1st Ionization Energy: 538 kJ·mol-1
2nd Ionization Energy: 1067 kJ·mol-1
3rd Ionization Energy: 1850 kJ·mol-1
CAS Number: 7439-91-0
EC Number: 231-099-0
MDL Number: MFCD00011066
Beilstein Number: N/A
SMILES Identifier: [La]
InChI Identifier: InChI=1S/La
PubChem CID: 23926
ChemSpider ID: 22369
Earth - Total: 379 ppb 
Mercury - Total: 291 ppb 
Venus - Total: 397 ppb 
Earth - Seawater (Oceans), ppb by weight: 0.0034
Earth - Seawater (Oceans), ppb by atoms: 0.00015
Earth -  Crust (Crustal Rocks), ppb by weight: 34000
Earth -  Crust (Crustal Rocks), ppb by atoms: 5000
Sun - Total, ppb by weight: 2
Sun - Total, ppb by atoms: 0.01
Stream, ppb by weight: 0.2
Stream, ppb by atoms: 0.001
Meterorite (Carbonaceous), ppb by weight: 290
Meterorite (Carbonaceous), ppb by atoms: 40
Typical Human Body, ppb by weight: N/A
Typical Human Body, ppb by atom: N/A
Universe, ppb by weight: 2
Universe, ppb by atom: 0.02
Discovered By: Carl Gustaf Mosander
Discovery Date: 1838
First Isolation: Friedrich Oskar Giesel (1902)

Health, Safety & Transportation Information for Lanthanum

Lanthanum is somewhat toxic. Safety data for Lanthanum and its compounds can vary widely depending on the form. For potential hazard information, toxicity, and road, sea and air transportation limitations, such as DOT Hazard Class, DOT Number, EU Number, NFPA Health rating and RTECS Class, please see the specific material or compound referenced in the Products tab. The below information applies to elemental (metallic) Lanthanum

Safety Data
Material Safety Data Sheet MSDS
Signal Word Danger
Hazard Statements H260
Hazard Codes N/A
Risk Codes N/A
Safety Precautions N/A
RTECS Number N/A
Transport Information UN 3208 4.3/PG 1
WGK Germany 3
Globally Harmonized System of
Classification and Labelling (GHS)

Lanthanum Isotopes

Naturally occurring lanthanum (La) has one stable isotope: 139La.

Nuclide Isotopic Mass Half-Life Mode of Decay Nuclear Spin Magnetic Moment Binding Energy (MeV) Natural Abundance
(% by atom)
117La 116.95007(43)# 23.5(26) ms ß+ to 117Ba; p to 116Cs (3/2+,3/2-) N/A 927.83 -
118La 117.94673(32)# 200# ms ß+ to 118Ba N/A N/A 945.23 -
119La 118.94099(43)# 1# s ß+ to 119Ba 11/2-# N/A 953.31 -
120La 119.93807(54)# 2.8(2) s ß+ to 120Ba; ß+ + p to 119Cs N/A N/A 970.7 -
121La 120.93301(54)# 5.3(2) s ß+ to 121Ba; ß+ + p to 120Cs 11/2-# N/A 978.78 -
122La 121.93071(32)# 8.6(5) s ß+ to 122Ba; ß+ + p to 121Cs N/A N/A 986.86 -
123La 122.92624(21)# 17(3) s ß+ to 123Ba 11/2-# N/A 1004.25 -
124La 123.92457(6) 29.21(17) s ß+ to 124Ba (7-,8-) N/A 1012.33 -
125La 124.920816(28) 64.8(12) s ß+ to 125Ba (11/2-) N/A 1020.41 -
126La 125.91951(10) 54(2) s ß+ to 126Ba (5)(+#) N/A 1037.81 -
127La 126.916375(28) 5.1(1) min ß+ to 127Ba (11/2-) N/A 1045.89 -
128La 127.91559(6) 5.18(14) min ß+ to 128Ba (5+) N/A 1053.96 -
129La 128.912693(22) 11.6(2) min ß+ to 129Ba 3/2+ N/A 1062.04 -
130La 129.912369(28) 8.7(1) min ß+ to 130Ba 3(+) N/A 1070.12 -
131La 130.91007(3) 59(2) min ß+ to 131Ba 3/2+ N/A 1078.2 -
132La 131.91010(4) 4.8(2) h EC to 132Ba 2- N/A 1086.28 -
133La 132.90822(3) 3.912(8) h EC to 133Ba 5/2+ N/A 1103.67 -
134La 133.908514(21) 6.45(16) min EC to 134Ba 1+ N/A 1111.75 -
135La 134.906977(11) 19.5(2) h EC to 135Ba 5/2+ N/A 1119.83 -
136La 135.90764(6) 9.87(3) min EC to 136Ba 1+ N/A 1127.91 -
137La 136.906494(14) 6(2)E+4 y EC to 137Ba 7/2+ 2.7 1135.99 -
138La 137.907112(4) 1.02(1)E+11 y ß+ to 138Ba; ß- to 138Ce 5+ 3.7139 1144.07 0.09
139La 138.9063533(26) STABLE - 7/2+ 2.7832 1152.15 99.91
140La 139.9094776(26) 1.6781(3) d ß- to 140Ce 3- N/A 1160.22 -
141La 140.910962(5) 3.92(3) h ß- to 141Ce (7/2+) N/A 1158.99 -
142La 141.914079(6) 91.1(5) min ß- to 142Ce 2- N/A 1167.07 -
143La 142.916063(17) 14.2(1) min ß- to 143Ce (7/2)+ N/A 1175.14 -
144La 143.91960(5) 40.8(4) s ß- to 144Ce (3-) N/A 1183.22 -
145La 144.92165(10) 24.8(20) s ß- to 145Ce; ß- + n to 144Ce (5/2+) N/A 1181.99 -
146La 145.92579(8) 6.27(10) s ß- to 146Ce; ß- + n to 146Ce 2- N/A 1190.06 -
147La 146.92824(5) 4.015(8) s ß- to 147Ce; ß- + n to 146Ce (5/2+) N/A 1198.14 -
148La 147.93223(6) 1.26(8) s ß- to 148Ce; ß- + n to 147Ce (2-) N/A 1196.91 -
149La 148.93473(34)# 1.05(3) s ß- to 149Ce; ß- + n to 148Ce 5/2+# N/A 1204.98 -
150La 149.93877(43)# 510(30) ms ß- to 150Ce; ß- + n to 149Ce (3+) N/A 1213.06 -
151La 150.94172(43)# 300# ms [>300 ns] ß- to 151Ce 5/2+# N/A 1211.82 -
152La 151.94625(43)# 200# ms [>300 ns] ß- to 152Ce N/A N/A 1219.9 -
153La 152.94962(64)# 150# ms [>300 ns] ß- to 153Ce 5/2+# N/A 1227.98 -
154La 153.95450(64)# 100# ms ß- to 154Ce N/A N/A 1226.74 -
155La 154.95835(86)# 60# ms ß- to 155Ce 5/2+# N/A 1234.82 -