Template:Infobox promethium

Promethium,  ₆₁Pm

Spectral lines of promethium
General properties
Name, symbol	promethium, Pm
Appearance	metallic
Pronunciation	/proʊˈmiːθiəm/ pro-MEE-thee-əm
Promethium in the periodic table
– ↑ Pm ↓ Np neodymium ← promethium → samarium
Atomic number (Z)	61
Group, block	group n/a, f-block
Period	period 6
Element category	lanthanide
Standard atomic weight (Ar)	[145]
Electron configuration	[Xe] 4f5 6s2
per shell	2, 8, 18, 23, 8, 2
Physical properties
Phase	solid
Melting point	1315 K ​(1042 °C, ​1908 °F)
Boiling point	3273 K ​(3000 °C, ​5432 °F)
Density near r.t.	7.26 g/cm3
Heat of fusion	7.13 kJ/mol
Heat of vaporization	289 kJ/mol
Atomic properties
Oxidation states	3, 2 ​(a mildly basic oxide)
Electronegativity	Pauling scale: 1.13 (?)
Ionization energies	1st: 540 kJ/mol 2nd: 1050 kJ/mol 3rd: 2150 kJ/mol
Atomic radius	empirical: 183 pm
Covalent radius	199 pm
Miscellanea
Crystal structure	​double hexagonal close-packed (dhcp)
Thermal expansion	9.0 µm/(m·K) (at r.t.)
Thermal conductivity	17.9 W/(m·K)
Electrical resistivity	est. 0.75 µΩ·m (at r.t.)
Magnetic ordering	paramagnetic
Young's modulus	α form: est. 46 GPa
Shear modulus	α form: est. 18 GPa
Bulk modulus	α form: est. 33 GPa
Poisson ratio	α form: est. 0.28
CAS Number	7440-12-2
History
Discovery	Chien Shiung Wu, Emilio Segrè, Hans Bethe (1942)
First isolation	Charles D. Coryell, Jacob A. Marinsky, Lawrence E. Glendenin, Harold G. Richter (1945)
Named by	Grace Mary Coryell (1945)
Most stable isotopes of promethium
iso NA half-life DM DE (MeV) DP 145Pm syn 17.7 y ε 0.163 145Nd 146Pm syn 5.53 y ε 1.472 146Nd β− 1.542 146Sm 147Pm trace 2.6234 y β− 0.224 147Sm

References

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