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Isotopes of Einsteinium

List, data and properties of all known isotopes of Einsteinium as well as radioactive decay products and intermediate products.

 

Einsteinium isotopes

Einsteinium isotopes include all of the atomic nuclei of the chemical element einsteinium; these consist of an atomic nucleus with 99 protons and in the uncharged state of 99 electrons. The difference between the individual einsteinium isotopes lies in the number of neutrons in the nucleus - and thus in the mass number.

Einsteinium

is an artificially created chemical element, of which 17 different isotopes have been created and characterized so far. Einsteinium-253 was the first nuclide to be discovered in the nuclear fallout of a hydrogen bomb test in 1952.

Einsteinium-252 has the longest half-life at 472 days.

 

Isotope Table: Einsteinium

 

Atomic Properties

Isotope
Nuclide
ZANNameAtomic Mass
[Nuclear Mass]
{Mass Excess}
Spin I
(h/2π)
μParent
123456789
240Es99240141Einsteinium-240240.06892(43) u
[240.0146185 u]
{64.19857 MeV}
(1+)
241Es99241142Einsteinium-241241.06856(24) u
[241.0142585 u]
{63.86323 MeV}
(3/2-)245Md
242Es99242143Einsteinium-242242.06957(27) u
[242.0152685 u]
{64.80404 MeV}
246Md
243Es99243144Einsteinium-243243.06951(22) u
[243.0152085 u]
{64.74815 MeV}
(7/2+)247Md
244Es99244145Einsteinium-244244.07088(19) u
[244.0165785 u]
{66.02429 MeV}
248Md
245Es99245146Einsteinium-245245.07125(21) u
[245.0169485 u]
{66.36895 MeV}
(3/2-)249Md
246Es99246147Einsteinium-246246.07289(24) u
[246.0185885 u]
{67.8966 MeV}
250Md
247Es99247148Einsteinium-247247.073622(21) u
[247.0193205 u]
{68.57845 MeV}
(7/2+)251Md
247Fm
248Es99248149Einsteinium-248248.07547(6) u
[248.0211685 u]
{70.29985 MeV}
(2-,0+)
249Es99249150Einsteinium-249249.07641(3) u
[249.0221085 u]
{71.17546 MeV}
7/2+
250Es99250151Einsteinium-250250.07861(11) u
[250.0243085 u]
{73.22474 MeV}
(6+)
250mEs99250151Einsteinium-250m250.07861(11) u
[250.0243085 u]
{73.22474 MeV}
1(-)
251Es99251152Einsteinium-251251.079992(6) u
[251.0256905 u]
{74.51207 MeV}
3/2-255Md
251Fm
252Es99252153Einsteinium-252252.08298(5) u
[252.0286785 u]
{77.29537 MeV}
(5-)256Md
253Es99253154Einsteinium-253253.0848213(13) u
[253.0305198 u]
{79.01053 MeV}
7/2+4.10(7)257Md
253Fm
253Cf
254Es99254155Einsteinium-254254.088021(4) u
[254.0337195 u]
{81.99103 MeV}
(7+)4.35(41)258Md
254mEs99254155Einsteinium-254m254.088021(4) u
[254.0337195 u]
{81.99103 MeV}
2+2.90(7)
255Es99255156Einsteinium-255255.090274(12) u
[255.0359725 u]
{84.08969 MeV}
(7/2+)255Cf
256Es99256157Einsteinium-256256.09360(11) u
[256.0392985 u]
{87.18784 MeV}
(1+,0-)
256mEs99256157Einsteinium-256m256.09360(11) u
[256.0392985 u]
{87.18784 MeV}
(8+)
257Es99257158Einsteinium-257257.09598(44) u
[257.0416785 u]
{89.40479 MeV}
(7/2+)

 

Radioactive Decay Properties

IsotopeRadioactive DecayAEExtern
Half-lifeDecay ModeProbabilityEnergy
1101112131415
Es-2406(2) sα → 236Bk
EC/β+240Cf
EC, SS div
70(10) %
30(10) %
8.23(57) MeV

Es-241ca. 8 sα → 237Bk
EC/β+241Cf
?
?
8.25(2) MeV
4.54(28) MeV
AL
Es-24213.5(25) sα → 238Bk
EC/β+242Cf
> 0 %
> 0 %
8.16(2) MeV
5.41(26) MeV
AL
Es-24321(2) sα → 239Bk
EC/β+243Cf
SF
61(6) %
39(6) %
< 1 %
8.072(10) MeV
3.76(24) MeV
AL
Es-24437(4) sα → 240Bk
EC → 244Cf
ca. 4 %
ca. 96 %
7.94(10) MeV
4.55(18) MeV
AL
Es-2451.1(1) minα → 241Bk
EC → 245Cf
40(10) %
60(10) %
7.9090(3) MeV
2.98(20) MeV
AL
Es-2467.5(5) minα → 242Bk
EC/β+246Cf
9.9(18) %
90.1(18) %
7.74(10) MeV
3.81(22) MeV
+x keVAL
Es-2474.55(26) minα → 243Bk
EC/β+247Cf
7 %
93 %

AL
Es-24824(3) minα → 244Bk
EC → 248Cf
0.25 %
99.7(3) %
7.16(5) MeV
3.06(5) MeV
AL
Es-249102.2(6) minα → 245Bk
EC/β+249Cf
0.57(8) %
99.43(8) %
6.94(3) MeV
1.45(3)
AL
Es-2508.6(1) hα → 246Bk
EC → 250Cf
< 3 %
> 97 %
6.83(12) MeV
2.05(10) MeV
AL
Es-250m2.22(5) hEC → 250Cf≤ 100 %+x keVAL
Es-25133(1) hα → 247Bk
EC → 251Cf
0.5(2) %
99.5(2) %
6.598(3) MeV
0.377(7) MeV
AL
Es-252471.7(19) dα → 248Bk
EC → 252Cf
78(2) %
22(2) %
6.79(5) MeV
1.26(5) MeV
AL
Es-25320.47(3) dα → 249Bk
SF div
< 100 %
0.0000087 %
6.73924(5) MeV
AL
Es-254275.7(5) dα → 250Bk
EC → 254Cf
SF div
β-254Fm
ca. 100 %
?
< 1 %
< 1 %
6.6157(15) MeV
0.649(12) MeV

1.088(3) MeV
AL
Es-254m39.3(2) hβ-254Fm
Iso → 254Es
α → 250Bk
EC → 254Cf
SF div

< 3 %
0.32(1) %
0.076(7) %
< 0.045 %




84.2(25) keVAL
Es-25539.8(12) dα → 251Bk
SF div
β-255Fm
8.0(4) %
0.0041(2) %
92 %
6.4363(13) MeV

0.290(10) MeV
AL
Es-25625.4(24) minβ-256Fm100 %1.70(10) MeVAL
Es-256m7.6 hβ-256Fm
SF, β-
99.998 %
0.002 %

+x keVAL
Es-2577.7(2) dβ-257Fm
SF div
?
?
0.81(41) MeV
AL

 

Notes (related to the columns):

1 - nuclide, isotope symbol.
2 - Z = number of protons (atomic number).
3 - Mass number A.
4 - N = number of neutrons.
5 - Identification of the Einsteinium isotope.
6 - Relative atomic mass of the Einsteinium 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.
7 - Nuclear spin I, unit: h/2π.
8 - Nuclear magnetic moment μmag.
9 - 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.
10 - Decay: Half-live of the Einsteinium isotope (a = years; ; d = days; h = hours; min = minutes; s = seconds).
11 - Decay: 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.
12 - Decay percentage in percent (%).
13 - Decay energy; Particle energy related to decay type.
14 - AE = Excitation energy for metastable nuclei.
15 - 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.

 

Radiation Protection

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

NuclideLimit ValueHASS limitSCDaughter NuclidesHalf-life
Es-250106 Bq100 Bq/g8.6 h
Es-251107 Bq100 Bq/g33.0 h
Es-253105 Bq100 Bq/g1 Bq cm-220.5 d
Es-254+104 Bq0,1 Bq/g1 Bq cm-2Bk-250275.7 d
Es-254m+106 Bq10 Bq/g1 Bq cm-2Bk-250, Fm-25439.3 h

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

 

Literature Sources and References

Properties of the Einsteinium 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.

Einsteinium: NMR properties

[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.

 


Category: Isotopes

Last update: 05.07.2020



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