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


Name Terbium Symbol Tb
atomic number 65 Atomic weight 158.9254
Density @ 293 K 8.27 g/cm3 Atomic volume 19.2 cm3/mol
Group Rare Earth, Lanthanides discovered 1843


state (s, l, g) s
melting point 1633.2 K boiling point 3073 K
Heat of fusion 10.80 kJ/mol Heat of vaporization 330.90 kJ/mol
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1st ionization energy 564.7 kJ/mole electronegativity 1.21
2nd ionization energy 1112 kJ/mole electron affinity 50 kJ/mole
3rd ionization energy 2114 kJ/mole Specific heat 0.18 J/gK
heat atomization 389 kJ/mole atoms

Oxidation & Electrons

Shells 2,8,18,27,8,2 electron configuration [Xe] 4f9 6s2
minimum oxidation number 0 maximum oxidation number 4
min. common oxidation no. 0 max. common oxidation no. 3
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Appearance & Characteristics

structure hcp: hexagonal close pkd color silvery-white
uses alloys toxicity
hardness mohs characteristics soft


reaction with air vigorous, = Tb4O7 (approx.) reaction with 6M HCl mild, = H2, TbCl3
reaction with 6M HCl mild, = H2, TbCl3 reaction with 15M HNO3 mild, = Tb(NO3)3
reaction with 6M NaOH
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Other Forms

number of isotopes 1 hydride(s) TbH2 TbH3
oxide(s) TbO2 Tb4O7 chloride(s) TbCl3


ionic radius (2- ion) pm ionic radius (1- ion) pm
atomic radius 177 pm ionic radius (1+ ion) pm
ionic radius (2+ ion) pm ionic radius (3+ ion) 106.3 pm
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thermal conductivity 11.1 J/m-sec-deg electrical conductivity 8.8 1/mohm-cm
polarizability 25.5 A^3


source Monazite(phosphate),bastnaesite rel. abund. solar system -1.220 log
abundance earth's crust 0 log cost, pure 1800 $/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.