We Use Cookies
We use cookies and other tracking technologies to improve your browsing experience on our website, to show you personalized content and targeted ads, to analyze our website traffic, and to understand where our visitors are coming from. For more information, please review our cookie policy and privacy policy.
By choosing I Accept, you consent to our use of cookies and other tracking technologies.

Promethium (Pm)

From Wikipedia, the free encyclopediaPromethium, originally prometheum, is a chemical element with the symbol Pm and atomic number 61. All of its isotopes are radioactive; it is one of only two such elements that are followed in the periodic table by elements with stable forms, a distinction shared with technetium. Chemically, promethium is a lanthanide, which forms salts when combined with other elements.

Promethium in the periodic table

Atomic number61
Element categoryLanthanide

Physical properties

Phase at STPSolid
Density7.26 g/cm3
Atomic weight145 u
Melting point1315 K
1041.85 °C
1907.33 °F
Boiling point3273 K
2999.85 °C
5431.73 °F

Atomic properties

Electronegativity (Pauling Scale)1.13
Electron affinity12.45 kJ/mol
Oxidation states+2, +3
(a mildly basic oxide)
Ionization energies
1540 kJ/mol
2 1050 kJ/mol
3 2150 kJ/mol
4 3970 kJ/mol

Electron configuration

Elektronkonfiguration (shorthand)[Xe] 4f5 6s2
Electron configuration1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f5 5s2 5p6 6s2
Electrons per shell2, 8, 18, 23, 8, 2


Discovered byChien Shiung Wu
Emilio Segrè
Hans Bethe
Named byIsotopes of promethium
Warning: Undefined variable $footer in /customers/a/d/1/periodictable.one/httpd.www/inc/footer.php on line 34