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Name: Promethium Symbol: Pm
Group: Rare Earth, Lanthanides Atomic weight: (145)
Density @ 293 K: 6.475 g/cm3 Atomic volume: 22.39 cm3/mol
Group: Rare Earth, Lanthanides discovered: 1945


state (s, l, g): s
melting point: 1353.2 K boiling point: K
Heat of fusion: ? Heat of vaporization: ?


1st ionization energy: 535.9 kJ/mole
electronegativity: 1.15 2nd ionization energy: 1052 kJ/mole
electron affinity: 50 kJ/mole 3rd ionization energy: 2150 kJ/mole
Specific heat: 0.18 J/gK heat atomization: 301 kJ/mole atoms

Oxidation & Electrons:

Shells: 2,8,18,23,8,2 electron configuration: [Xe] 4f5 6s2
minimum oxidation number: 0 maximum oxidation number: 3
min. common oxidation no.: 0 max. common oxidation no.: 3

Appearance & Characteristics:

structure: cp: close packed (ABCB) color: silvery-white
uses: nuclear battery toxicity:
hardness: mohs characteristics: Radioactive


reaction with air: vigorous, =>Pm2O3
reaction with 6M HCl: mild, =>H2, PmCl3 reaction with 6M HCl: mild, =>H2, PmCl3
reaction with 15M HNO3: mild, =>Pm(NO3)3 reaction with 6M NaOH:

Other Forms:

number of isotopes: 0 hydride(s):
oxide(s): Pm2O3 chloride(s):


ionic radius (2- ion): pm ionic radius (1- ion): pm
atomic radius: 183 pm ionic radius (1+ ion): pm
ionic radius (2+ ion): pm ionic radius (3+ ion): 111 pm


thermal conductivity: 17.9 J/m-sec-deg
electrical conductivity: 1/mohm-cm polarizability: 30.1 A^3


source: Synthetic
rel. abund. solar system: log abundance earth's crust: -19.3 log
cost, pure: $/100g cost, bulk: $/100g