Isotopes of berkelium
{{Short description|none}}
{{Infobox berkelium isotopes}}
Berkelium (97Bk) is an artificial element, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 243Bk in 1949. There are nineteen known radioisotopes, from 233Bk to 253Bk (except 235Bk and 237Bk), and seven nuclear isomers. The longest-lived isotope known is 247Bk with a half-life of 1,380 years; however 248Bk, which has not been observed to decay, may live longer.
List of isotopes
{{Anchor|Berkelium-235|Berkelium-237|Berkelium-250m3|Berkelium-254}}
{{Isotopes table
|symbol=Bk
|refs=NUBASE2020, AME2020 II
|notes=m, unc(), mass#, exen#, spin(), spin#, SF, EC
}}
|-id=Berkelium-233
| rowspan=2|233Bk
| rowspan=2 style="text-align:right" | 97
| rowspan=2 style="text-align:right" | 136
| rowspan=2|233.05665(25)#
| rowspan=2|{{val|40|(30)|u=s}}
| α (82%)
| 229Am
| rowspan=2|3/2−#
|-
| β+? (18%)
| 233Cm
|-id=Berkelium-234
| rowspan=2|234Bk
| rowspan=2 style="text-align:right" | 97
| rowspan=2 style="text-align:right" | 137
| rowspan=2|234.05732(16)#
| rowspan=2|{{val|20|(5)|u=s}}
| α (>80%)
| 230Am
| rowspan=2|3−#
|-
| β+ (<20%)
| 234Cm
|-id=Berkelium-236
| rowspan=2|236Bk
| rowspan=2 style="text-align:right" | 97
| rowspan=2 style="text-align:right" | 139
| rowspan=2|236.05748(39)#
| rowspan=2|{{val|26|(10)|u=s}}
| β+ (99.96%)
| 236Cm
| rowspan=2|4+#
|-
| β+, SF (0.04%)
| (various)
|-id=Berkelium-238
| rowspan=2|238Bk
| rowspan=2 style="text-align:right" | 97
| rowspan=2 style="text-align:right" | 141
| rowspan=2|238.05820(28)#
| rowspan=2|{{val|2.40|(8)|u=min}}
| β+ (99.95%)
| 238Cm
| rowspan=2| 1#
|-
| β+, SF (0.048%)
| (various)
|-id=Berkelium-239
| 239Bk
| style="text-align:right" | 97
| style="text-align:right" | 142
| 239.05824(22)#
| 100# s
| β+
| 239Cm
| (7/2+)
|-id=Berkelium-240
| rowspan=3|240Bk
| rowspan=3 style="text-align:right" | 97
| rowspan=3 style="text-align:right" | 143
| rowspan=3|240.05976(16)#
| rowspan=3|{{val|4.8|(8)|u=min}}
| β+?
| 240Cm
| rowspan=3|7−#
|-
| α?
| 236Am
|-
| β+, SF (0.0013%)
| (various)
|-id=Berkelium-241
| 241Bk
| style="text-align:right" | 97
| style="text-align:right" | 144
| 241.06010(18)#
| {{val|4.6|(4)|u=min}}
| β+
| 241Cm
| (7/2+)
|-id=Berkelium-242
| rowspan=2|242Bk
| rowspan=2 style="text-align:right" | 97
| rowspan=2 style="text-align:right" | 145
| rowspan=2|242.06200(14)#
| rowspan=2|{{val|7.0|(13)|u=min}}
| β+
| 242Cm
| rowspan=2|3+#
|-
| β+, SF (<3×10−5%)
| (various)
|-id=Berkelium-242m
| style="text-indent:1em" | 242mBk
| colspan="3" style="text-indent:2em" | 2000(200)# keV
| {{val|600|(100)|u=ns}}
| SF
| (various)
|
|-id=Berkelium-243
| rowspan=2|243Bk
| rowspan=2 style="text-align:right" | 97
| rowspan=2 style="text-align:right" | 146
| rowspan=2|243.063006(5)
| rowspan=2|{{val|4.6|(2)|u=h}}
| β+ (99.85%)
| 243Cm
| rowspan=2|3/2−
|-
| α (0.15%)
| 239Am
|-id=Berkelium-244
| rowspan=2|244Bk
| rowspan=2 style="text-align:right" | 97
| rowspan=2 style="text-align:right" | 147
| rowspan=2|244.065179(15)
| rowspan=2|{{val|5.02|(3)|u=h}}
| β+? (99.994%)
| 244Cm
| rowspan=2|4−
|-
| α (0.006%)
| 240Am
|-id=Berkelium-244m
| style="text-indent:1em" | 244mBk
| colspan="3" style="text-indent:2em" | 1500(500)# keV
| {{val|820|(60)|u=ns}}
| SF
| (various)
|
|-id=Berkelium-245
| rowspan=2|245Bk
| rowspan=2 style="text-align:right" | 97
| rowspan=2 style="text-align:right" | 148
| rowspan=2|245.0663598(19)
| rowspan=2|{{val|4.95|(3)|u=d}}
| EC (99.88%)
| 245Cm
| rowspan=2|3/2−
|-
| α (0.12%)
| 241Am
|-id=Berkelium-246
| 246Bk
| style="text-align:right" | 97
| style="text-align:right" | 149
| 246.06867(6)
| {{val|1.80|(2)|u=d}}
| β+
| 246Cm
| 2(−)
|-id=Berkelium-247
| 247Bk
| style="text-align:right" | 97
| style="text-align:right" | 150
| 247.070306(6)
| {{val|1.38e3|(25)|u=y}}
| α
| 243Am
| 3/2−
|-id=Berkelium-248
| rowspan=3|248Bk
| rowspan=3 style="text-align:right" | 97
| rowspan=3 style="text-align:right" | 151
| rowspan=3|248.07314(5)
| rowspan=3|>9 y
| α?
| 244Am
| rowspan=3|6+#
|-
| EC?
| 248Cm
|-
| β−?
| 248Cf
|-id=Berkelium-248m
| rowspan=2 style="text-indent:1em" | 248mBk{{r|g=n|OGI|r=Order of ground state and isomer is uncertain.}}
| rowspan=2 colspan="3" style="text-indent:2em" | −20(50) keV
| rowspan=2| 23.7(2) h
| β− (70%)
| 248Cf
| rowspan=2| 1(−)
|-
| EC (30%)
| 248Cm
|-id=Berkelium-249
| rowspan=3|249Bk
| rowspan=3 style="text-align:right" | 97
| rowspan=3 style="text-align:right" | 152
| rowspan=3|249.0749831(13)
| rowspan=3|{{val|327.2|(3)|u=d}}
| β−
| 249Cf
| rowspan=3|7/2+
|-
| α (0.00145%)
| 245Am
|-
| SF (4.7×10−8%)
| (various)
|-id=Berkelium-249m
| style="text-indent:1em" | 249mBk
| colspan="3" style="text-indent:2em" | 8.777(14) keV
| {{val|300|u=us}}
| IT
| 249Bk
| 3/2−
|-id=Berkelium-250
| 250Bk
| style="text-align:right" | 97
| style="text-align:right" | 153
| 250.078317(3)
| {{val|3.212|(5)|u=h}}
| β−
| 250Cf
| 2−
|-id=Berkelium-250m1
| style="text-indent:1em" | 250m1Bk
| colspan="3" style="text-indent:2em" | 35.59(10) keV
| {{val|29|(1)|u=us}}
| IT
| 250Bk
| 4+
|-id=Berkelium-250m2
| style="text-indent:1em" | 250m2Bk
| colspan="3" style="text-indent:2em" | 85.6(16) keV
| {{val|213|(8)|u=us}}
| IT
| 250Bk
| 7+
|-id=Berkelium-251
| 251Bk
| style="text-align:right" | 97
| style="text-align:right" | 154
| 251.080761(12)
| {{val|55.6|(11)|u=min}}
| β−
| 251Cf
| (3/2−)
|-id=Berkelium-251m
| style="text-indent:1em" | 251mBk
| colspan="3" style="text-indent:2em" | 35.5(13) keV
| {{val|58|(4)|u=us}}
| IT
| 251Bk
| (7/2+)
|-id=Berkelium-252
| 252Bk
| style="text-align:right" | 97
| style="text-align:right" | 155
| 252.08431(22)#
| {{val|1.8|(5)|u=min}}
| β−
| 252Cf
|
|-id=Berkelium-253
| 253Bk
| style="text-align:right" | 97
| style="text-align:right" | 156
| 253.08688(39)#
| 60# min
| β−?
| 253Cf
| 3/2-#
{{Isotopes table/footer}}
Actinides vs fission products
{{Actinides vs fission products}}
{{clear}}
References
{{Reflist}}
- Isotope masses from:
- {{NUBASE 2003}}
- Half-life, spin, and isomer data selected from the following sources.
- {{NUBASE 2003}}
- {{NNDC}}
- {{CRC85|chapter=11}}
{{Navbox element isotopes}}