Thorium

Symbol ThAtomic number 90
Atomic mass
232.038
Thermal conductivity
0.540
Atomic radius
...
Covalent radius
1.65
Density
11.7
Atomic volume
19.9
Melting point
2028
Oxidation states
4
Boiling point
5061
Stable isotopes
1
Heat of vapor.
514.4
Electronegativity
1.3
Heat of fusion
16.1
First ionization
6.08
Specific heat
0.12
Electrical conduct.
...
Electron configuration

General descriptionNuclear data
Index

Periodic Table

Chemistry concepts
 
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Thorium

Thorium is found in nature in the form of the oxide thorite, ThO2, which forms crystals as thorianite . It appears in the form of thorium phosphate in monazite sand. Thorium is found in the mineral aeschynite and euxenite.

Thorium has been used in the manufacture of mantles for gas lanterns. The fabric of the mantles is saturated with thorium nitrate and cerium nitrate. The burning of the mantles leaves a residue of thorium and cerium dioxides. This residue glows with a brilliant white luminescence when heated to a high temperature by the gas flame. The presence of the thorium makes these mantles slightly radioactive, so recent mantles have replaced these oxides with other illuminants.

Thorium-232 is one of the small number of isotopes which can be made to undergo nuclear fission, so it could be employed as a nuclear fuel.

Atomic dataNuclear data
Index

Periodic Table

Chemistry concepts

Reference
Pauling
Ch. 29
 
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Thorium Nuclear Data

Z
A
Atomic
Mass (u)
Nuclear
Mass(GeV/c2
Binding
Energy(MeV)
Spin
Natural
Abund.
Half-life
Decay
Q
MeV
90
227
227.027703
211.4307
1736.0
3/2
...
18.72d
a
6.15
90
228
228.028715
212.3631
1743.0
0
...
1.912y
a
5.52
90
229
229.031755
213.2975
1748.4
5/2
...
7.9ky
a
5.17
90
230
230.033128
214.2302
1755.2
0
...
75.4ky
a
4.77
90
231
231.036298
215.1647
1760.3
5/2
...
35.2h
b-
0.39
90
232
232.038051
216.0978
1766.7
0
1.00
1.4x1010y
a
4.08
90
234
234.043593
217.9660
1777.7
0
...
24.10d
b-
0.27
Atomic data
Index

Periodic Table

Chemistry concepts

Reference
Rohlf
 
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