Chemicool

Th

90

232.0381
Thorium
General | States | Energies | Oxidation & Electrons |Appearance & Characteristics
Reactions | Other Forms |Radius | Conductivity | Abundance
Encyclopedia Britannica articles

General

Name Thorium Symbol Th
atomic number 90 Atomic weight 232.0381
Density @ 293 K 11.7 g/cm3 Atomic volume 19.9 cm3/mol
Group Rare Earth, Actinides discovered 1829

States

state (s, l, g) s
melting point 2023.2 K boiling point 5123 K
Heat of fusion 16.10 kJ/mol Heat of vaporization 514.40 kJ/mol
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Energies

1st ionization energy 587 kJ/mole electronegativity 1.3
2nd ionization energy 1110 kJ/mole electron affinity kJ/mole
3rd ionization energy 1930 kJ/mole Specific heat 0.12 J/gK
heat atomization 576 kJ/mole atoms

Oxidation & Electrons

Shells 2,8,18,32,18,10,2 electron configuration [Rn] 6d2 7s2
minimum oxidation number 0 maximum oxidation number 4
min. common oxidation no. 0 max. common oxidation no. 4
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Appearance & Characteristics

structure fcc: face-centered cubic color white
uses gas mantles (ThO2) toxicity
hardness mohs characteristics Radioactive

Reactions

reaction with air mild, w/ht ignites = ThO2 reaction with 6M HCl mild
reaction with 6M HCl mild reaction with 15M HNO3 passivated
reaction with 6M NaOH none
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Other Forms

number of isotopes 3 hydride(s) ThH2 Th4H15
oxide(s) ThO2 chloride(s) ThCl4

Radius

ionic radius (2- ion) pm ionic radius (1- ion) pm
atomic radius 179 pm ionic radius (1+ ion) pm
ionic radius (2+ ion) pm ionic radius (3+ ion) pm
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Conductivity

thermal conductivity 54 J/m-sec-deg electrical conductivity 76.923 1/mohm-cm
polarizability 32.1 A^3

Abundance

source Monazite(phosphate),U extractn rel. abund. solar system -1.475 log
abundance earth's crust 1 log cost, pure $/100g
cost, bulk $/100g
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