Lanthanide

Promethium

Promethium (Pm) has atomic number 61. PubChem classifies it as lanthanide.

Atomic number

61

Symbol

Pm

Atomic weight (source value)

144.91276

Electron configuration

[Xe]6s2 4f5

Standard state

Solid

Electronegativity (Pauling)

Not provided

Melting point (K)

1315

Boiling point (K)

3273

Density (g/cm³)

7.26

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.