Isotopes of einsteinium

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Einsteinium (Es) has no stable isotopes. A standard atomic mass cannot be given.

[edit] Table

nuclide
symbol
Z(p) N(n)  
isotopic mass (u)
 
half-life nuclear
spin
representative
isotopic
composition
(mole fraction)
range of natural
variation
(mole fraction)
excitation energy
240Es 99 141 240.06892(43)# 1# s
241Es 99 142 241.06854(24)# 10(5) s [8(+6-5) s] (3/2-)
242Es 99 143 242.06975(35)# 13.5(25) s
243Es 99 144 243.06955(25)# 21(2) s 3/2-#
244Es 99 145 244.07088(20)# 37(4) s
245Es 99 146 245.07132(22)# 1.1(1) min (3/2-)
246Es 99 147 246.07290(24)# 7.7(5) min 4-#
247Es 99 148 247.07366(3)# 4.55(26) min 7/2+#
248Es 99 149 248.07547(6)# 27(5) min 2-#,0+#
249Es 99 150 249.07641(3)# 102.2(6) min 7/2+
250Es 99 151 250.07861(11)# 8.6(1) h (6+)
250mEs 200(150)# keV 2.22(5) h 1(-)
251Es 99 152 251.079992(7) 33(1) h (3/2-)
252Es 99 153 252.08298(5) 471.7(19) d (5-)
253Es 99 154 253.0848247(28) 20.47(3) d 7/2+
254Es 99 155 254.088022(5) 275.7(5) d (7+)
254mEs 84.2(25) keV 39.3(2) h 2+
255Es 99 156 255.090273(12) 39.8(12) d (7/2+)
256Es 99 157 256.09360(11)# 25.4(24) min (1+,0-)
256mEs 0(100)# keV 7.6 h (8+)
257Es 99 158 257.09598(44)# 7.7(2) d 7/2+#
258Es 99 159 258.09952(32)# 3# min

[edit] Notes

  • Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses.
  • Uncertainties are given in concise form in parentheses after the corresponding last digits. Uncertainty values denote one standard deviation, except isotopic composition and standard atomic mass from IUPAC which use expanded uncertainties.

[edit] References


Isotopes of californium Isotopes of einsteinium Isotopes of fermium
Index to isotope pages