alpha particle spectrum of thorium from
Washington State's Public Health Laboratories

Th - Thorium

A long halflife radioactive metal, thorium was identified in 1821and isolated by J. J. Berzelius in 1828 in Sweden. Thorium is used in gas lamp mantles and nuclear breeder reactors.

Atomic number - 90 Density g/mL 11 .7
Atomic weight u 232 .03804 Melting point K 2028
Bonding radius A 1 .65 Boiling point K 5061
Atomic radius A - Heat of vaporization kJ/mol 514 .4
Ionization Potential V 6 .08 Heat of fusion kJ/mol 16 .1
Electronegativity - 1 .3 Specific heat J/gK 0 .12
The oxide is a weak base.
Crystal are face centered cubic.

Electron config. : [Rn] 6d2 7s2

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
H He
Li Be B C N O F Ne
Na Mg Al Si P S Cl Ar
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe
Cs Ba La* Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Fr Ra Ac** Rf Db Sg Bh Hs Mt 110 111 112 113
Lanthanides* Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
Actinides ** Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

Isotopes of Th: Click mass number for decay process, product for element page.
210
9 msec
a,8.200 MeV
Ra-206
210.0 		211
37 msec
a/EC,7.940
Ra-207/Ac-211
211.01481 		212
30 msec
a/EC,7.952
Ra-208/Ac-212
212.01291 		213
140 msec
a,7.840 MeV
Ra-209
213.01295 		214
100 msec
a,7.826 MeV
Ra-210
214.01145 		215
1.2 sec
a,7.666 MeV
Ra-211
215.01172 		216
0.028 sec
a/EC,8.071
Ra-212/Ac-216
216.01105
216a
180 usec
a,10.099 MeV
Ra-212
216.01322 		217
0.252 msec
a,9.424 MeV
Ra-213
217.01306 		218
109 nsec
a,9.849 MeV
Ra-214
218.01326 		219
1.05 usec
a,9.510 MeV
Ra-215
219.01552 		220
9.7 usec
a/EC,8.953
Ra-216/Ac-220
220.01573 		221
1.68 msec
a,8.628 MeV
Ra-217
221.01817 		222
2.8 msec
a,8.129 MeV
Ra-218
222.01845
223
0.60 sec
a,7.567 MeV
Ra-219
223.02078 		224
1.05 sec
a,7.304 MeV
Ra-220
224.02145 		225
8.72 min
a/EC,6.922
Ra-221/Ac-225
225.02394 		226
30.57 min
a,6.451 MeV
Ra-222
226.02489 		227
18.72 da
a,6.146 MeV
Ra-223
227.02769 		228
1.9131 yr
a,5.520 MeV
Ra-224
228.02873 		229
7880 yr
a,5.168 MeV
Ra-225
229.03175
230
7.538E+4 yr
a/SF,4.770
Ra-226/?
230.03312 		231
25.52 hr
a/B-,2.100
Ra-227/Pa-231
231.03629 		232 100%
1.405E10 yr
a/SF,4.083
Ra-228/?
232.03804 		233
22.3 min
B-,1.245 MeV
Pa-233
233.04157 		234
24.10 da
B-,6.420 MeV
Pa-234
234.04359 		235
7.1 min
B-,1.930 MeV
Pa-235
235.04750 		236
37.5 min
B-,6.000 MeV
Pa-236
236.05014
237
5.0 min
B-,1.710 MeV
Pa-237
237.0 		MASS abund.
Halflife
Particle, Energy
Decay Product(s)
Isotopic Mass

Updated by clh on 2/6/98. This is not a publication of Phoenix College.