Lanthanide

Lanthanum

Lanthanum (La) has atomic number 57. PubChem classifies it as lanthanide.

Atomic number

57

Symbol

La

Atomic weight (source value)

138.9055

Electron configuration

[Xe]6s2 5d1

Standard state

Solid

Electronegativity (Pauling)

1.1

Melting point (K)

1191

Boiling point (K)

3737

Density (g/cm³)

6.15

Oxidation states

+3

Understanding this entry

Atomic number is the number of protons in the nucleus. Properties are reference values and may depend on conditions and measurement conventions. An atomic weight is not the mass of every isotope. For elements without a standard atomic weight, a source may report an isotope mass number. Blank source values are shown as unavailable rather than estimated.

Further reading and reference: NIH PubChem source dataset ↗. Values and educational summaries are not a substitute for specialised advice.