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Isotopes of Mendelevium

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

 

Mendelevium isotopes

All of the atomic nuclei of the chemical element Mendelevium are summarized under Mendelevium isotopes; these consist of an atomic nucleus with 101 protons and in the uncharged state of 101 electrons. The difference between the individual Mendelevium isotopes lies in the number of neutrons in the nucleus.

 

Mendelevium is an exclusively synthetically produced radioactive chemical element that is not known in nature. So far, 16 different Md isotopes are known, of which the nuclide 258Md is the longest-lived with a half-life of 51.3 days.

 

Isotope Table: Mendelevium

 

Atomic Properties

Isotope
Nuclide
ZANNameAtomic Mass
[Nuclear Mass]
{Mass Excess}
Spin I
(h/2π)
μParent
123456789
244Md101244143Mendelevium-244244 u
[243.9446017 u]
{0 MeV}
245Md101245144Mendelevium-245245.08081(33) u
[245.0254117 u]
{75.27403 MeV}
(1/2-)
245mMd101245144Mendelevium-245m245.08081(33) u
[245.0254117 u]
{75.27403 MeV}
(7/2)
246Md101246145Mendelevium-246246.08171(28) u
[246.0263117 u]
{76.11237 MeV}
247Md101247146Mendelevium-247247.08152(22) u
[247.0261217 u]
{75.93539 MeV}
(7/2-)
248Md101248147Mendelevium-248248.08282(25) u
[248.0274217 u]
{77.14633 MeV}
249Md101249148Mendelevium-249249.08291(22) u
[249.0275117 u]
{77.23017 MeV}
(7/2-)253Lr
249mMd101249148Mendelevium-249m249.08291(22) u
[249.0275117 u]
{77.23017 MeV}
(1/2-)
250Md101250149Mendelevium-250250.08441(32) u
[250.0290117 u]
{78.62741 MeV}
254Lr
251Md101251150Mendelevium-251251.084774(20) u
[251.0293757 u]
{78.96647 MeV}
(7/2-)255Lr
252Md101252151Mendelevium-252252.08643(14) u
[252.0310317 u]
{80.50903 MeV}
256Lr
253Md101253152Mendelevium-253253.08714(3) u
[253.0317417 u]
{81.17039 MeV}
(7/2-)257Lr
254Md101254153Mendelevium-254254.08959(11) u
[254.0341917 u]
{83.45255 MeV}
258Lr
254mMd101254153Mendelevium-254m254.08959(11) u
[254.0341917 u]
{83.45255 MeV}
255Md101255154Mendelevium-255255.091083(7) u
[255.0356847 u]
{84.84327 MeV}
(7/2-)259Lr
255No
256Md101256155Mendelevium-256256.09389(13) u
[256.0384917 u]
{87.45797 MeV}
(1-)260Lr
257Md101257156Mendelevium-257257.0955380(17) u
[257.0401397 u]
{88.99307 MeV}
(7/2-)
258Md101258157Mendelevium-258258.098430(5) u
[258.0430317 u]
{91.68695 MeV}
(8-)
258mMd101258157Mendelevium-258m258.098430(5) u
[258.0430317 u]
{91.68695 MeV}
(1-)
259Md101259158Mendelevium-259259.10051(21) u
[259.0451117 u]
{93.62446 MeV}
7/2-~259No
260Md101260159Mendelevium-260260.10365(34) u
[260.0482517 u]
{96.54935 MeV}

 

Radioactive Decay Properties

IsotopeRadioactive DecayAEExtern
Half-lifeDecay ModeProbabilityEnergy
1101112131415
Md-2440.4 sα → 240Es8.66(2) MeV
Md-2450.90(25) msα → 241Es
SF → div
?
?
8.98(21) MeV
AL
Md-245mca. 0.35 sα → 241Es
EC/β+245Fm
?
selten

~ 300 keVAL
Md-2460.9(2) sα → 242Es
SF → div
EC → 246Fm
?
?
?
8.89(4) MeV

5.93(26) MeV
+x keVAL
Md-2471.2(1) sα → 243Es
SF div
> 99.9 %
< 0.1 %
8.764(10) MeV
AL
Md-2487(3) sα → 244Es
EC → 248Fm
20(10) %
80(10) %
8.70(15) MeV
5.25(24) MeV
AL
Md-24921.7(20) sα → 245Es
EC/β+249Fm
> 60 %
≤ 40 %
8.441(18) MeV
3.71(20) MeV
AL
Md-249m1.9(9) s+x keVAL
Md-25052(6) sα → 246Es
EC → 250Fm
7(3) %
93(3) %
8.30(20) MeV
4.56(30) MeV
AL
Md-2514.0(5) minα → 247Es
EC/β+251Fm
≤ 10 %
≥ 90 %
7.963(4) MeV
3.013(24) MeV
AL
Md-2522.3(8) minEC → 252Fm≤ 100 %3.69(13) MeVAL
Md-253ca. 6 minEC/β+253Fm
α → 249Es
99.3 %
0.7 %
1.83(3) MeV
7.573(8) MeV
AL
Md-25410(3) minEC/β+254Fm≤ 100 %2.55(10) MeVAL
Md-254m28(8) minEC/β+254Fm≤ 100 %+x keVAL
Md-25527(2) minEC/β+255Fm
α → 251Es
93(1) %
7(1) %
1.043(8) MeV
7.9059(26) MeV
AL
Md-25677.7(18) minEC → 256Fm
α → 252Es
SF div.
90.8(7) %
9.2(7) %
< 3 %
1.97(12) MeV
7.74(11) MeV
AL
Md-2575.52(5) hEC → 257Fm
α → 253Es
SF div
85 %
15 %
< 1 %
0.403(5) MeV
7.5576(10)
AL
Md-25851.50(29) dα → 254Es
SF, ε div
~100 %
≤ 0.003 %
7.2713(19) MeV
AL
Md-258m57.0(9) minEC → 258Fm
β-258No
SF, β- div
α → 254Es
70 %
10 %
20 %
< 1.2 %
1.26(20) MeV
0.210(100) MeV

7.2713(19) MeV
+x keVAL
Md-2591.60(6) hSF div
α → 255Es
< 100 %
< 1.3 %

7.11(20) MeV
AL
Md-26031.8(5) dSF div
α → 256Es
EC → 260Fm
β-260No

≤ 25 %
≤ 23 %
≤ 10 %

6.94(30) MeV

0.94(37) 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 Mendelevium isotope.
6 - Relative atomic mass of the Mendelevium 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 Mendelevium 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 Mendelevium radionuclides:

NuclideLimit ValueHASS limitSCDaughter NuclidesHalf-life
Md-257107 Bq10 Bq/g5.5 h
Md-258+105 Bq10 Bq/gFm-254, Fm-258, No-25851.5 h

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

 

Literature Sources and References

Properties of the Mendelevium 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.

Mendelevium: 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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