Lanthanum

Atomic number

57

Atomic mass (u)

138.9055

Category

Lanthanide

Standard state

Solid

Melting point

917.85 °C (1191 K)

Boiling point

3463.85 °C (3737 K)

Density (g/cm³)

6.15

Electronegativity (Pauling)

1.1

Electron configuration

[Xe]6s2 5d1

Oxidation states

+3

Atomic radius (pm)

240

First ionization energy (eV)

5.577

Discovery & recognition

Discovery year / period (PubChem)

1839

Discovery credited to (RSC)

Carl Gustav Mosander

Date or period recorded by RSC

1839

Discovery place

Stockholm, Sweden

An ancient date does not identify a first human discovery. Different references may date observation, isolation and formal recognition differently.

Natural occurrence & production

The creation of an element’s nuclei and its concentration into terrestrial deposits are different processes. The occurrence note below concerns its presence or production on Earth; it is not a complete account of nucleosynthesis.

“Lanthanum is found in ‘rare earth’ minerals, principally monazite (25% lanthanum) and bastnaesite (38% lanthanum).”

Royal Society of Chemistry · occurrence excerpt ↗

Continue the research

Reference values are not product specifications. Blank values have not been estimated. For superheavy elements, some properties and family assignments are theoretical or incompletely measured.