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Isotopes of Uranium

List, data and properties of all known isotopes of Uranium.

Content
Atomic properties
Decay properties
NMR active nuclides
Radiation protection
References
Uranium isotopes

The chemical element uranium has no stable isotopes and occurs in nature as a mixture of three different radioactive nuclides:

 

Naturally Occurring Uranium Isotopes

Atomic Mass maQuantityHalf-lifeSpin
Uranium
Isotopic mixture		238,02891 u100 %
Isotope 234U234,04095(2) u0,0054(5) %2.455(6) × 105 a0+
Isotope 235U235,04393(2) u0,7204(6) %7.04(1) × 108 a7/2-
Isotope 238U238,05079(2) u99,2742(10) %4.468(6) × 109 a0+

 

In addition, extremely small traces of the nuclide uranium-236 can be detected in nature. The relative atomic mass of the natural uranium isotope mixture is given as 238.02891(3) u.

Pure uranium isotopes - in particular uranium-235 and uranium-238 - play in all areas of nuclear technology, nuclear weapon technology and as a starting material an important role for the generation of nuclides of other elements.

 

Isotope Table: Uranium

The two following tables list the most important data and properties of the Uranium isotopes. Further information on the individual Uranium isotopes is listed on separate pages and can be accessed via the link in column 1.

 

Atomic Properties

Isotope
Nuclide		ENAtomic Mass
[Nuclear Mass]
{Mass Excess}		Spin I
(h/2π)		Parent
123456
Uranium-21421492U122214 u
[213.9495373 u]
{0 MeV}		0+
Uranium-21521592U123215.02676(9) u
[214.9762973 u]
{24.92678 MeV}		5/2-
Uranium-21621692U124216.02476(3) u
[215.9742973 u]
{23.06379 MeV}		0+
Uranium-216m216m92U124216.02476(3) u
[215.9742973 u]
{23.06379 MeV}		(8+)
Uranium-21721792U125217.02466(8) u
[216.9741973 u]
{22.97064 MeV}
Uranium-21821892U126218.023505(15) u
[217.9730423 u]
{21.89477 MeV}		0+
Uranium-218m218m92U126218.023505(15) u
[217.9730423 u]
{21.89477 MeV}		(8+)
Uranium-21921992U127219.02500(5) u
[218.9745373 u]
{23.28735 MeV}
Uranium-22022092U128220 u
[219.9495373 u]
{0 MeV}
Uranium-22122192U129221.026320(80) u
[220.9758573 u]
{24.51692 MeV}		(9/2+)
Uranium-22222292U130222.02606(6) u
[221.9755973 u]
{24.27473 MeV}		0+
Uranium-22322392U131223.02774(8) u
[222.9772773 u]
{25.83964 MeV}
Uranium-22422492U132224.027614(25) u
[223.9771513 u]
{25.72228 MeV}		0+228Pu
Uranium-22522592U133225.029385(11) u
[224.9789223 u]
{27.37195 MeV}		229Pu
Uranium-22622692U134226.029339(14) u
[225.9788763 u]
{27.3291 MeV}		0+230Pu
Uranium-22722792U135227.031182(10) u
[226.9807193 u]
{29.04585 MeV}		(3/2+)231Pu
Uranium-22822892U136228.031371(15) u
[227.9809083 u]
{29.2219 MeV}		0+232Pu
Uranium-22922992U137229.033506(6) u
[228.9830433 u]
{31.21064 MeV}		(3/2+)233Pu
Uranium-23023092U138230.033940(5) u
[229.9834773 u]
{31.61491 MeV}		0+234Pu
230Pa
230Np
Uranium-23123192U139231.0362923(29) u
[230.9858296 u]
{33.80606 MeV}		(5/2-)235Pu
231Np
Uranium-23223292U140232.0371549(1) u
[231.9866922 u]
{34.60957 MeV}		0+236Pu
232Np
232Pa
Uranium-23323392U141233.0396343(24) u
[232.9891716 u]
{36.91911 MeV}		5/2+237Pu
233Np
233Pa
Uranium-23423492U142234.04095(2) u
[233.9904873 u]
{38.14468 MeV}		0+238Pu
234Np
234Pa
234mPa
Uranium-234m234m92U142234.04095(2) u
[233.9904873 u]
{38.14468 MeV}		6-
Uranium-23523592U143235.04393(2) u
[234.9934673 u]
{40.92053 MeV}		7/2-239Pu
235Np
235Pa
Uranium-235m235m92U143235.04393(2) u
[234.9934673 u]
{40.92053 MeV}		1/2+
Uranium-235m2235m292U143235.04393(2) u
[234.9934673 u]
{40.92053 MeV}
Uranium-23623692U144236.0455661(12) u
[235.9951034 u]
{42.44455 MeV}		0+240Pu
236Np
236Pa
Uranium-236m1236m192U144236.0455662(12) u
[235.9951035 u]
{42.44464 MeV}		(4)-
Uranium-236m2236m292U144236.0455662(12) u
[235.9951035 u]
{42.44464 MeV}		(0+)
Uranium-23723792U145237.0487284(13) u
[236.9982657 u]
{45.39021 MeV}		1/2+241Pu
237Pa
Uranium-237m237m92U145237.0487284(13) u
[236.9982657 u]
{45.39021 MeV}		(7/2)-
Uranium-23823892U146238.05079(2) u
[238.0003273 u]
{47.31058 MeV}		0+242Pu
238Pa
Uranium-238m238m92U146238.05079(2) u
[238.0003273 u]
{47.31058 MeV}		0+
Uranium-23923992U147239.0542920(16) u
[239.0038293 u]
{50.57267 MeV}		5/2+239Pa
Uranium-239m1239m192U147239.0542920(16) u
[239.0038293 u]
{50.57267 MeV}		1/2+
Uranium-239m2239m292U147239.0542920(16) u
[239.0038293 u]
{50.57267 MeV}		(5/2+)
Uranium-24024092U148240.0565924(27) u
[240.0061297 u]
{52.71548 MeV}		0+244Pu
Uranium-24124192U149241.06033(21) u
[241.0098673 u]
{56.19703 MeV}		7/2+
Uranium-24224292U150242.06293(22) u
[242.0124673 u]
{58.61892 MeV}		0+
Uranium-24324392U151243.06708(32) u
[243.0166173 u]
{993.97862 MeV}

 

Radioactive Decay Properties

IsotopeRadioactive DecayExtern
Half-lifeDecay ModeProbabilityEnergy
789101112
U-2140.52 msα → 210Th100 %8.692(18) MeVAL
U-2150.7(+13-3) msα → 211Th
EC/β+ → 214Pa		> 0 %
?		8.59(5) MeV
7.06(11) MeV
U-2164.5 msα → 212Th8.531(26) MeV
U-216m0.7 msα → 212Th
Iso → 216U		> 0 %
?
U-21716 msα → 213Th
EC/β+ → 216Pa		100 %
?		8.43(7) MeV
AL
U-2180.51 msα → 214Th100 %8.775(9) MeVAL
U-218m0.56 msα → 214Th100 %AL
U-219ca. 42 μ sα → 215Th100 %9.94(5) MeVAL
U-220- ungelistet -AL
U-2210.66(14) μsα → 217Th~100 %9.889(71) MeVAL
U-2224.7(7) mu;sα → 218Th100 %9.48(5) MeVAL
U-223ca. 18 μsα → 219Th
EC/β+ → 223Pa		ca. 100 %
ca. 0.2 %		8.94(5) MeV
3.52(10) MeV		AL
U-2240.84 msα → 220Th100 %8.628(7) MeVAL
U-22569(15) msα → 221Th100 %8.007(6) MeVAL
U-226268(9) msα → 222Th100 %7.701(4) MeVAL
U-2271.1(1) minα → 223Th100 %7.235(3) MeVAL
U-2289.1(2) minα → 224Th
EC → 228Pa		> 95 %
< 5 %		6.804(10) MeV
0.299(15) MeV		AL
U-22958(3) minα → 225Th
EC → 229Pa		ca. 20 %
ca. 80 %		6.476(3) MeV
1.314(7) MeV		AL
U-23020.23(2) dα → 226Th100 %5.9924(5) MeVAL
U-2314.2(1) dα → 227Th
EC → 231Pa		0.004(1) %
ca. 100 %		5.5763(17) MeV
0.382(3) MeV		AL
U-23268.9(4) aα → 228Th
SF div		ca. 100 %
Spuren		5.41363(9) MeV
AL
U-2331.5919(15) × 105 aα → 229Th
SF div		100 %
Spuren		4.9087(12) MeV
AL
U-2342.455(6) × 105 aα → 230Th
SF div		ca. 100 %
Spuren		4.8575(7) MeV
AL
U-234m33.5(20) μs
U-2357.04(1) × 108 aα → 231Th
SF div		ca. 100 %
Spuren		4.6780(7) MeV
AL
U-235mca. 26 minIso → 235U100 %AL
U-235m23.6(19) msSF div?
U-2362.342(4) × 107 aα → 232Th
SF div		ca. 100 %
selten		4.5730(9) MeV
AL
U-236m1100(4) ns
U-236m2120(2) nsIso → 236U
SF
α → 232Th		87(6) %
13(6) %
U-2376.752(2) dβ- → 237Np100 %0.5185(5) MeVAL
U-237m155(6) ns
U-2384.468(6) × 109 aα → 234Th
SF div		ca. 100 %
10-5 %		4.2699(21) MeV
AL
U-238m280(6) nsIso → 238U
SF div		97.4(4) %
2.6(4) %
AL
U-23923.45(2) minβ- → 239Np100 %1.2617(15) MeVAL
U-239m10.78(4) μs
U-239m20.25 μs
U-24014.1(1) hβ- → 240Np100 %4.035(14) MeVAL
U-241ca. 40 minβ- → 241Np1.88(22) MeVAL
U-24216.8(5) minβ- → 242Np100 %1.20(28) MeVAL
U-243β- → 243Np?2.67 MeV

 

Notes (related to the columns):

1 - name of the nuclide, isotope.
2 - E: isotope symbol with mass number (superscript; number of nucleons) and Atomic number (subscript; number of protons).
3 - N: number of neutrons.
4 - relative atomic mass of the Uranium isotope (isotopic mass including electrons) and the mass of the atomic nucleus in square brackets (nuclear mass, nuclide mass without electrons), each related to 12C = 12.00000 [2]. In addition, the mass excess is given in MeV.
5 - nuclear spin I, unit: h/2π.
6 - source nuclides: Possible, assumed or actual source nuclides (mother nuclides, parent nuclides). If applicable, the corresponding decay modes can be found in the data for the respective starting nuclide.

7 - isotope notation in short form.
8 - decay: half-live of the Uranium isotope (a = years; ; d = days; h = hours; min = minutes; s = seconds).
9 - decay mode: type of decay into the respective daughter nuclides with n = neutron emission; p = proton emission; α = alpha decay; β- = beta minus decay with electron emission; EC = electron capture; β+ = positron emission; ε = β+ and/or EC; Iso = isomeric transition; CD = cluster decay; SF = spontaneous decay.
10 - decay probability in percent (%).
11 - decay energy; Particle energy related to decay type.
12 - other information and notes: AL = Adopted Levels (link to external data [1]).

Miscellaneous:

()- Numbers in brackets: uncertainty to represent the spread of the reported value.
~ - Theoretical values or systematic trends.
  - unlisted-: Nuclides that have already been mentioned in the literature but for some reason can no longer be found in the current nuclide tables because their discovery e.g. has not confirmed.

 

NMR active Uranium nuclides

Nuclide
quantity 1)
spin		Nuclear
magnetic
moment
μ/μN		Gyromagnetic ratio
{Quadrupole moment}		Resonant
frequency
v0 bei 1 T		Relative
sensitivity
H0 = const.
v0 = const. 3)
235U
0,7204(6) %
7/2-		- 0,38(3)0,4926
{+ 4,936(6)}		0,830,00015
0,4082

1) Quantity Percentage of natural occurrence.

2) Gyromagnetic ratio: 107 rad T-1 s-1
    Quadrupole moment: Q [barn] = [100 fm2]

3) Related to 1H = 1,000.

 

Radiation Protection

According to the Radiation Protection Ordinance (StrlSchV 2018, Germany), the following values (columns 1 to 7) apply to the handling of Uranium radionuclides:

NuclideLimit ValueHASS limitSCDaughter NuclidesHalf-life
U-230+105 Bq10 Bq/g0,04 TBq0,1 Bq cm-2Th-226, Ra-222, Rn-218,
Po-214		20.8 d
U-231107 Bq100 Bq/g10 Bq cm-24.2 d
U-232+103 Bq0,1 Bq/g0,06 TBq0,1 Bq cm-2Th-228, Ra-224, Rn-220,
Po-216, Pb-212, Bi-212,
Tl-208, Po-212		68.9 a
U-233104 Bq1 Bq/g0,07 TBq1 Bq cm-2160000 a
U-234104 Bq1 Bq/g1 Bq cm-2250000 a
U-235+104 Bq1 Bq/g0,00008 TBq1 Bq cm-2Th-2317.0 × 108 a
U-236104 Bq10 Bq/g0,2 TBq1 Bq cm-22.4 × 107 a
U-237106 Bq100 Bq/g10 Bq cm-26.8 d
U-238+104 Bq1 Bq/gUnbegrenzt (UL)1 Bq cm-2Th-234, Pa-234m, Pa-2344.5 × 109 a
U-238sec103 Bq1 Bq/g1 Bq/cm24.4 × 109 a
U-239106 Bq100 Bq/g100 Bq cm-223.5 min
U-240+106 Bq100 Bq/g10 Bq cm-214.1 h

(HASS = High-Activity Sealed Radioactive Sources; SC = surface contamination)

 

Literature Sources and References

Properties of the Uranium nucleides

[1] - NuDat: National Nuclear Data Center, Brookhaven National Laboratory, based on ENSDF and the Nuclear Wallet Cards.

[2] - G. Audi et. al.: The NUBASE evaluation of nuclear and decay properties. Nuclear Physics, (2003), DOI 10.1016/j.nuclphysa.2003.11.001.

[3] - Live Chart of Nuclides. Nuclear structure and decay data.

Uranium: NMR properties - 235U-NMR

[4] - N. J. Stone: Table of nuclear magnetic dipole and electric quadrupole moments. Atomic Data and Nuclear Data Tables, (2005), DOI 10.1016/j.adt.2005.04.001.

[5] - Pekka Pyykkö: Year-2008 nuclear quadrupole moments. Molecular Physics, (2008), DOI 10.1080/00268970802018367.

[6] - Pekka Pyykkö: Year-2017 nuclear quadrupole moments. Molecular Physics, (2018), DOI 10.1080/00268976.2018.1426131.

[7] - N. J. Stone: Table of recommended nuclear magnetic dipole moments. IAEA, (2019).

More sources:

[8] - Isotopic abundances, atomic weights and isotopic masses: see respective keyword.

[9] - C. Fry, M. Thoennessen:
Discovery of actinium, thorium, protactinium, and uranium isotopes.
In: Atomic Data and Nuclear Data Tables, (2013), DOI 10.1016/j.adt.2012.03.002.

 

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