isotopes of einsteinium

Einsteinium (₉₉Es) is a synthetic element, and thus a standard atomic weight cannot be given. Like all synthetic elements, it has no stable isotopes. The first isotope to be discovered (in nuclear fallout from the Ivy Mike H-bomb test) was ²⁵³Es in 1952. There are 18 known radioisotopes from ²⁴⁰Es to ²⁵⁷Es, and 4 nuclear isomers. The longest-lived isotope is ²⁵²Es with a half-life of 471.7 days, or around 1.293 years.

List of isotopes

{{Anchor|Einsteinium-239|Einsteinium-243m|Einsteinium-247m|Einsteinium-251m|Einsteinium-253m|Einsteinium-258}}

{{Isotopes table

|symbol=Es

|refs=NUBASE2020, AME2020 II

|notes=m, unc(), mass#, exen#, spin(), spin#, SF, EC, IT

}}

|-id=Einsteinium-240

| rowspan=3|²⁴⁰Es

| rowspan=3 style="text-align:right" | 99

| rowspan=3 style="text-align:right" | 141

| rowspan=3|240.06895(39)#

| rowspan=3|6.0(17) s

| α (70%)

| ²³⁶Bk

| rowspan=3|4−#

| β⁺ (30%)

| ²⁴⁰Cf

| β⁺, SF (0.16%)

| (various)

|-id=Einsteinium-241

| rowspan=2|²⁴¹Es{{cite journal |last1=Khuyagbaatar |first1=J. |last2=Albers |first2=H. M. |last3=Block |first3=M. |last4=Brand |first4=H. |last5=Cantemir |first5=R. A. |last6=Di Nitto |first6=A. |last7=Düllmann |first7=Ch. E. |last8=Götz |first8=M. |last9=Götz |first9=S. |last10=Heßberger |first10=F. P. |last11=Jäger |first11=E. |last12=Kindler |first12=B. |last13=Kratz |first13=J. V. |last14=Krier |first14=J. |last15=Kurz |first15=N. |last16=Lommel |first16=B. |last17=Lens |first17=L. |last18=Mistry |first18=A. |last19=Schausten |first19=B. |last20=Uusitalo |first20=J. |last21=Yakushev |first21=A. |title=Search for Electron-Capture Delayed Fission in the New Isotope ²⁴⁴Md |journal=Physical Review Letters |date=1 October 2020 |volume=125 |issue=14 |pages=142504 |doi=10.1103/PhysRevLett.125.142504 |pmid=33064498 |bibcode=2020PhRvL.125n2504K |s2cid=223546973 |url=http://urn.fi/URN:NBN:fi:jyu-202010066084 }}

| rowspan=2 style="text-align:right" | 99

| rowspan=2 style="text-align:right" | 142

| rowspan=2|241.06859(25)#

| rowspan=2|{{val|4.3|2.4|1.2|u=s}}

| α

| ²³⁷Bk

| rowspan=2|3/2−#

| β⁺?

| ²⁴¹Cf

|-id=Einsteinium-242

| rowspan=3|²⁴²Es{{cite journal | last=Khuyagbaatar | first=J. | last2=Cantemir | first2=R. A. | last3=Düllmann | first3=Ch. E. | last4=Jäger | first4=E. | last5=Kindler | first5=B. | last6=Krier | first6=J. | last7=Kurz | first7=N. | last8=Lommel | first8=B. | last9=Schausten | first9=B. | last10=Yakushev | first10=A. | title=Decay properties of the neutron-deficient isotope Es 242 | journal=Physical Review C | volume=109 | issue=3 | date=2024-03-18 | issn=2469-9985 | doi=10.1103/PhysRevC.109.034311| arxiv=2408.01714 }}

| rowspan=3 style="text-align:right" | 99

| rowspan=3 style="text-align:right" | 143

| rowspan=3|242.06957(28)#

| rowspan=3|16.9(8) s

| β⁺

| ²⁴²Cf

| rowspan=3|2+#

| α (41%)

| ²³⁸Bk

| β⁺, SF (1.5%)

| (various)

|-id=Einsteinium-243

| rowspan=2|²⁴³Es

| rowspan=2 style="text-align:right" | 99

| rowspan=2 style="text-align:right" | 144

| rowspan=2|243.06951(22)#

| rowspan=2|22.1(14) s

| α (61%)

| ²³⁹Bk

| rowspan=2|(7/2+)

| β⁺ (39%)

| ²⁴³Cf

|-id=Einsteinium-244

| rowspan=3|²⁴⁴Es

| rowspan=3 style="text-align:right" | 99

| rowspan=3 style="text-align:right" | 145

| rowspan=3|244.07088(20)#

| rowspan=3|37(4) s

| β⁺ (95%)

| ²⁴⁴Cf

| rowspan=3|6+#

| α (5%)

| ²⁴⁰Bk

| β⁺, SF (0.011%)

| (various)

|-id=Einsteinium-245

| rowspan=2|²⁴⁵Es

| rowspan=2 style="text-align:right" | 99

| rowspan=2 style="text-align:right" | 146

| rowspan=2|245.07119(18)#

| rowspan=2|1.11(6) min

| β⁺ (51%)

| ²⁴⁵Cf

| rowspan=2|(3/2−)

| α (49%)

| ²⁴¹Bk

|-id=Einsteinium-245m

| rowspan=3 style="text-indent:1em" | ^245mEsOrder of ground state and isomer is uncertain.

| rowspan=3 colspan="3" style="text-indent:2em" | 30(15)# keV

| rowspan=3|>50# μs

| IT?

| ²⁴⁵Es

| rowspan=3|7/2+#

| α?

| ²⁴¹Bk

| β⁺?

| ²⁴⁵Cf

|-id=Einsteinium-246

| rowspan=3|²⁴⁶Es

| rowspan=3 style="text-align:right" | 99

| rowspan=3 style="text-align:right" | 147

| rowspan=3|246.072806(97)

| rowspan=3|7.5(5) min

| β⁺ (90.1%)

| ²⁴⁶Cf

| rowspan=3|4−#

| α (9.9%)

| ²⁴²Bk

| β⁺, SF (.003%)

| (various)

|-id=Einsteinium-247

| rowspan=3|²⁴⁷Es

| rowspan=3 style="text-align:right" | 99

| rowspan=3 style="text-align:right" | 148

| rowspan=3|247.073622(21)

| rowspan=3|4.55(26) min

| β⁺ (93%)

| ²⁴⁷Cf

| rowspan=3|(7/2+)

| α (7%)

| ²⁴³Bk

| SF?

| (various)

|-id=Einsteinium-248

| rowspan=3|²⁴⁸Es

| rowspan=3 style="text-align:right" | 99

| rowspan=3 style="text-align:right" | 149

| rowspan=3|248.075469(56)#

| rowspan=3|24(3) min

| β⁺ (99.75%)

| ²⁴⁸Cf

| rowspan=3|2−#

| α (.25%)

| ²⁴⁴Bk

| β⁺, SF (3.5×10⁻⁴%)

| (various)

|-id=Einsteinium-249

| rowspan=2|²⁴⁹Es

| rowspan=2 style="text-align:right" | 99

| rowspan=2 style="text-align:right" | 150

| rowspan=2|249.076409(32)#

| rowspan=2|102.2(6) min

| β⁺ (99.43%)

| ²⁴⁹Cf

| rowspan=2|7/2+

| α (.57%)

| ²⁴⁵Bk

|-id=Einsteinium-250

| rowspan=2|²⁵⁰Es

| rowspan=2 style="text-align:right" | 99

| rowspan=2 style="text-align:right" | 151

| rowspan=2|250.07861(11)#

| rowspan=2|8.6(1) h

| β⁺

| ²⁵⁰Cf

| rowspan=2|6(+)

| α?

| ²⁴⁶Bk

|-id=Einsteinium-250m

| rowspan=2 style="text-indent:1em" | ^250mEs

| rowspan=2 colspan="3" style="text-indent:2em" | 200(150)# keV

| rowspan=2|2.22(5) h

| β⁺

| ²⁵⁰Cf

| rowspan=2|1(−)

| α?

| ²⁴⁶Bk

|-id=Einsteinium-251

| rowspan=2|²⁵¹Es

| rowspan=2 style="text-align:right" | 99

| rowspan=2 style="text-align:right" | 152

| rowspan=2|251.0799914(57)

| rowspan=2|33(1) h

| EC (99.5%)

| ²⁵¹Cf

| rowspan=2|3/2−

| α (.5%)

| ²⁴⁷Bk

|-id=Einsteinium-252

| rowspan=2|²⁵²Es

| rowspan=2 style="text-align:right" | 99

| rowspan=2 style="text-align:right" | 153

| rowspan=2|252.082979(54)

| rowspan=2|471.7(19) d

| α (78(2)%)

| ²⁴⁸Bk

| rowspan=2|(4+)

| EC (22(2)%)

| ²⁵²Cf

|-id=Einsteinium-253

| rowspan=2|²⁵³EsMost common isotope

| rowspan=2 style="text-align:right" | 99

| rowspan=2 style="text-align:right" | 154

| rowspan=2|253.0848212(13)

| rowspan=2|20.47(3) d

| α

| ²⁴⁹Bk

| rowspan=2|7/2+

| SF (8.7×10⁻⁶%)

| (various)

|-id=Einsteinium-254

| rowspan=3|²⁵⁴Es

| rowspan=3 style="text-align:right" | 99

| rowspan=3 style="text-align:right" | 155

| rowspan=3|254.0880243(32)

| rowspan=3|275.7(5) d

| α{{r|g=n|EC254|r=Theoretically capable of electron capture to ²⁵⁴Cf{{NUBASE2020|ref}}}}

| ²⁵⁰Bk

| rowspan=3|7+

| β⁻ (1.74×10⁻⁴%)

| ²⁵⁴Fm

| SF (<3×10⁻⁶%)

| (various)

|-id=Einsteinium-254m

| rowspan=5 style="text-indent:1em" | ^254mEs

| rowspan=5 colspan="3" style="text-indent:2em" | 80.4(11) keV

| rowspan=5|39.3(2) h

| β⁻ (98(2)%)

| ²⁵⁴Fm

| rowspan=5|2+

| IT (<3%)

| ²⁵⁴Es

| α (0.32(1)%)

| ²⁵⁰Bk

| EC (0.076(7)%)

| ²⁵⁴Cf

| SF (<0.045%)

| (various)

|-id=Einsteinium-255

| rowspan=3|²⁵⁵Es

| rowspan=3 style="text-align:right" | 99

| rowspan=3 style="text-align:right" | 156

| rowspan=3|255.090274(12)

| rowspan=3|39.8(12) d

| β⁻ (92.0%)

| ²⁵⁵Fm

| rowspan=3|(7/2+)

| α (8.0%)

| ²⁵¹Bk

| SF (.0041%)

| (various)

|-id=Einsteinium-256

| rowspan=2|²⁵⁶Es

| rowspan=2 style="text-align:right" | 99

| rowspan=2 style="text-align:right" | 157

| rowspan=2| 256.09360(11)#

| rowspan=2|7.6 h

| β⁻

| ²⁵⁶Fm

| rowspan=2|7+#

| β⁻, SF (.002%)

| (various)

|-id=Einsteinium-256m

| style="text-indent:1em" |^256mEs

| colspan="3" style="text-indent:2em" | 0(100)# keV

| 25.4(12) min

| β⁻

| ²⁵⁶Fm

| 0+#

|-id=Einsteinium-257

| rowspan=2|²⁵⁷Es

| rowspan=2 style="text-align:right" | 99

| rowspan=2 style="text-align:right" | 158

| rowspan=2|257.09598(44)#

| rowspan=2|7.7(2) d

| β⁻

| ²⁵⁷Fm

| rowspan=2|7/2+#

| α?

| ²⁵³Bk

References

Isotope masses from:
{{NUBASE 2003}}
Half-life, spin, and isomer data selected from the following sources.
{{NUBASE 2003}}
{{NNDC}}
{{CRC85|chapter=11}}

Category:Einsteinium

Einsteinium