Lanthanum is used in alloys, optical glass, and catalysts. Lanthanum-nickel materials can store hydrogen, while lanthanum oxide modifies glass properties. It commonly occurs with other rare-earth elements, so separating chemically similar neighbors is part of the work required before making these materials.
FROM ELEMENT TO APPLICATION
AN ELEMENT IN CONTEXT
How can a solid alloy store hydrogen inside a rechargeable battery?
A lanthanum-containing metal-hydride electrode alloy provides a material that can take up hydrogen. It is a chemical host rather than an empty gas container.
Explore the model (optional)
LaFORM → INTERACTION → CONSEQUENCE
Follow the explanation in either direction. These are authored steps, not a physical clock.
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USE THE EXPLANATION
Which model best represents the hydrogen-bearing electrode?
Atomic identity, reference properties and structure models
INTERACTIVE 3D57 visible sites
An electron censusDrag to rotate · scroll or pinch to zoom
[Xe] 5d1 6s2. Grouping electrons by principal shell connects the neutral-atom configuration to periodic-table patterns.
What this representation means
A three-dimensional counting diagram. Dots are count markers, not measured electron positions; spherical placement and spacing are arbitrary. There are no electron trajectories here. Orbitals describe quantum states.
Carl Gustav Mosander recognized lanthanum in 1839 while examining material thought to be cerium . A fraction behaved differently during chemical separation, revealing another element. Axel Erdmann also identified lanthanum in a Norwegian that year. The name's association with hiding suits the evidence: an apparently familiar rare-earth preparation could conceal several elements whose similar chemistry made clean separation difficult.
1839
Lanthanum distinguished
Mosander separated a new constituent from cerium-containing material.
1839
Mineral occurrence recognized
Erdmann identified lanthanum in material from Norway.
Lanthanum occurs with other rare-earth elements in minerals including monazite and bastnaesite. Its chemistry makes neighboring elements persistent companions during processing. A rare-earth concentrate is therefore not automatically a supply of pure lanthanum: several separations may stand between a mineral mixture and a material selected for one application.
Lanthanum is a reactive metal, commonly encountered in compounds with trivalent lanthanum. Its uses depend strongly on surrounding atoms. Lanthanum oxide can modify optical glass, while lanthanum–nickel intermetallic materials interact reversibly with hydrogen. Neither application can be explained by the appearance of the pure metal alone.
Each section links its supporting references. Descriptions and diagrams were authored for this atlas. Source checks completed. Source checks dated 2026-09-06.
CITE THIS PAGE
Family labels and the group-3 layout are teaching conventions. A table position does not establish an unknown bulk property. Electronic configurations refer to neutral atoms; ions and material environments require their own account.
Read each reference property together with its units, conditions and the reference information below.
Not yet recorded: electron affinity, second ionization energy, ground-state term symbol, van der waals radius, thermal conductivity, specific heat capacity, electrical resistivity, crystal structure, lattice parameter a, space group, abundance in seawater, abundance in the universe, annual production, supply-risk listing, hazard classification, biological role, cas registry number, pubchem cid, wikidata item. These families are declared and awaiting an ingestion run against the source each names; they are listed here rather than shown as empty rows.
Physical
Intended reference: CRC Handbook of Chemistry and Physics · CRC Press
Phase at 20 °C
solid
293.15 K, 101.325 kPa
Melting point in K
1193 K
at standard pressure unless noted
Boiling point in K
3737 K
101.325 kPa
Density in g/cm³
6.14 g/cm³
solids and liquids at 293 K; gases at 273 K and 101.325 kPa
Atomic and electronic
Intended reference: Pauling electronegativity scale · Widely tabulated; original in The Nature of the Chemical Bond
Electronegativity in Pauling
1.1 Pauling
Pauling scale
First ionization energy in kJ/mol
538.1 kJ/mol
gas-phase neutral atom, ground state
Covalent radius in pm
207 pm
single-bond covalent radius
Common oxidation states
+3
states met in ordinary compounds; not exhaustive
Occurrence and identity
Intended reference: CRC Handbook of Chemistry and Physics · CRC Press
Abundance in the crust in mg/kg
39 mg/kg
upper continental crust, mass fraction
Has stable isotopes
Yesderived
Discovery year in CE
1839 CEderived
WHERE IT SITS AMONG ITS NEIGHBORS
Electronegativity across period 6
La 1.1 Pauling · Lanthanum
Electronegativity across period 6. Exact values.
Cs
0.79
Ba
0.89
La
1.1
Ce
1.12
Pr
1.13
Nd
1.14
Sm
1.17
Eu
1.2
Gd
1.2
Tb
1.1
Dy
1.22
Ho
1.23
Er
1.24
Tm
1.25
Yb
1.1
Lu
1.27
Hf
1.3
Ta
1.5
W
2.36
Re
1.9
Os
2.2
Ir
2.2
Pt
2.28
Au
2.54
Hg
2
Tl
1.62
Pb
2.33
Bi
2.02
Po
2
At
2.2
Electronegativity down group 3
La 1.1 Pauling · Lanthanum
Electronegativity down group 3. Exact values.
Sc
1.36
Y
1.22
La
1.1
Ac
1.1
The trend uses the same reference-property values as the periodic table. Elements with no recorded value are left out of the line rather than drawn at zero.
