U - Uranium

Uranium oxide has been used since Roman times for yellow pigments in glass. The element was discovered in 1789 by a German chemist, Martin Klaproth, who named it for the newly observed seventh planet. In 1841, French chemist Eugene Peligot extracted pure uranium metal, which caused little interest until March 1, 1869, when French physicist, Henry Becquerel serendipidously discovered radioactivity in uranium salts - suddenly uranium was hot stuff!

Although only mildly radioactive, uranium compounds are toxic.

Atomic number - 92 Density g/mL 18 .9

Atomic weight u 238 .029 Melting point K 1405

Bonding radius A 1 .42 Boiling point K 4407

Atomic radius A - Heat of vaporization kJ/mol 477

Ionization Potential V 6 .05 Heat of fusion kJ/mol 8 .52

Electronegativity - 1 .38 Specific heat J/gK 0 .12

The oxide is amphoteric.
Crystal are orthorhombic.

Electron config. : [Rn] 5f³ 6d¹ 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 U: Click mass number for decay process, product for element page.

218
1.5 msec
a,8.790 MeV
Th-214
218.02348 219
42 usec
a,9.900 MeV
Th-215
219.02495 222
1.0 usec
a,9.500 MeV
Th-218
222.02606 223
18 usec
a,8.940 MeV
Th-219
223.02771 224
0.9 msec
a,8.620 MeV
Th-220
224.02759 225
95 msec
a,8.020 MeV
Th-221
225.02938 226
200 msec
a,7.715 MeV
Th-222
226.02933

227
1.1 min
a,7.211 MeV
Th-223
227.03113 228
9.1 min
a/EC,6.804
Th-224/Pa-228
228.03136 229
58 min
a/EC,1.309
Th-225/Pa-229
229.03349 230
20.8 da
a,5.993 MeV
Th-226
230.03392 231
4.2 da
a/EC,5.149
Th-227/Pa-231
231.03626 232
68.9 yr
a/Ne,5.414
Th-228/?
232.03714 233
1.592E+5 yr
a/Ne/SF,4.909
Th-229/?/?
233.03962

234 0.0055%
2.455E+5 yr
a/SF,4.859
Th-230/?
234.04094 235 0.720%
703.8E+6 yr
a/Ne/SF,4.679
Th-231/?/?
235.04392 236
2.342E7 yr
a/SF,4.572
Th-232/?
236.04556 237
6.75 da
B-,2.250 MeV
Np-237
237.04872 238 99.2745%
4.468E+9 yr
a/SF,4.270
Th-234/?
238.05078 239
23.45 min
B-,1.265 MeV
Np-239
239.05428 240
14.1 hr
B-,3.900 MeV
Np-240
240.05658

242
16.8 min
B-,7.660 MeV
Np-242
242.06315 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.

Atomic number	-	92		Density	g/mL	18	.9
Atomic weight	u	238	.029	Melting point	K	1405
Bonding radius	A	1	.42	Boiling point	K	4407
Atomic radius	A	-		Heat of vaporization	kJ/mol	477
Ionization Potential	V	6	.05	Heat of fusion	kJ/mol	8	.52
Electronegativity	-	1	.38	Specific heat	J/gK	0	.12
The oxide is amphoteric.				Crystal are orthorhombic.
Electron config. : [Rn] 5f³ 6d¹ 7s²
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218 1.5 msec a,8.790 MeV Th-214 218.02348	219 42 usec a,9.900 MeV Th-215 219.02495	222 1.0 usec a,9.500 MeV Th-218 222.02606	223 18 usec a,8.940 MeV Th-219 223.02771	224 0.9 msec a,8.620 MeV Th-220 224.02759	225 95 msec a,8.020 MeV Th-221 225.02938	226 200 msec a,7.715 MeV Th-222 226.02933
227 1.1 min a,7.211 MeV Th-223 227.03113	228 9.1 min a/EC,6.804 Th-224/Pa-228 228.03136	229 58 min a/EC,1.309 Th-225/Pa-229 229.03349	230 20.8 da a,5.993 MeV Th-226 230.03392	231 4.2 da a/EC,5.149 Th-227/Pa-231 231.03626	232 68.9 yr a/Ne,5.414 Th-228/? 232.03714	233 1.592E+5 yr a/Ne/SF,4.909 Th-229/?/? 233.03962
234 0.0055% 2.455E+5 yr a/SF,4.859 Th-230/? 234.04094	235 0.720% 703.8E+6 yr a/Ne/SF,4.679 Th-231/?/? 235.04392	236 2.342E7 yr a/SF,4.572 Th-232/? 236.04556	237 6.75 da B-,2.250 MeV Np-237 237.04872	238 99.2745% 4.468E+9 yr a/SF,4.270 Th-234/? 238.05078	239 23.45 min B-,1.265 MeV Np-239 239.05428	240 14.1 hr B-,3.900 MeV Np-240 240.05658
242 16.8 min B-,7.660 MeV Np-242 242.06315	MASS abund. Halflife Particle, Energy Decay Product(s) Isotopic Mass