General | States | Energies | Oxidation & Electrons |Appearance & Characteristics
Reactions | Other Forms |Radius | Conductivity | Abundance
Encyclopedia Britannica articles


Name Promethium Symbol Pm
atomic number 61 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 ?
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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
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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
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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
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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
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World Wide Web presentation of Chemicool Periodic Table is © Copyright 1996-99 by David D. Hsu. Some data were provided by and used with the permission of JCE Software and is owned and copyright by the Division of Chemical Education, Inc. Additional data were provided by Perkin-Elmer through Peter Lykos of IIT. The information may not be redistributed without the permission of David Hsu or JCE Software.