Isotop fermium

**[[Fermium]]** (**<sub>100</sub>Fm**) adalah  sebuah unsur buatan, sehingga berat atom standarnya tidak dapat diberikan. Seperti semua unsur buatan, ia tidak memiliki satu pun isotop stabil. Isotop pertama yang ditemukan (dalam luruhan nuklir dari pengujian nuklir) adalah 255Fm pada tahun 1952. 250Fm disintesis secara independen tak lama setelah penemuan 255Fm. Ada 18 radioisotop yang diketahui, mulai dari 241Fm hingga 260Fm (260Fm belum dikonfirmasi), dan 2 isomer nuklir, 250mFm dan 251mFm. Isotop yang berumur paling panjang adalah 257Fm dengan waktu paruh 100,5 hari, dan isomer yang berumur paling panjang adalah 250mFm dengan waktu paruh 1,92 detik.

## Daftar isotop

|-
| rowspan=2|241Fm
| rowspan=2 style="text-align:right" | 100
| rowspan=2 style="text-align:right" | 141
| rowspan=2|241,07421(32)#
| rowspan=2|730(60)&nbsp;μdtk
| SF(>78%)
| (beberapa)
| rowspan=2|5/2#+
|-
| α (237Cf
|-
| rowspan=2|242Fm
| rowspan=2 style="text-align:right" | 100
| rowspan=2 style="text-align:right" | 142
| rowspan=2|242,07343(43)#
| rowspan=2|0,8(2)&nbsp;mdtk
| SF
| (beberapa)
| rowspan=2|0+
|-
| α (langka)
| 238Cf
|-
| rowspan=3|243Fm
| rowspan=3 style="text-align:right" | 100
| rowspan=3 style="text-align:right" | 143
| rowspan=3|243,07447(23)#
| rowspan=3|231(9)&nbsp;mdtk
| α (91%)
| 239Cf
| rowspan=3|7/2−#
|-
| SF (9%)
| (beberapa)
|-
| β+ (langka)
| 243Es
|-
| rowspan=2|244Fm
| rowspan=2 style="text-align:right" | 100
| rowspan=2 style="text-align:right" | 144
| rowspan=2|244,07404(22)#
| rowspan=2|3,12(8)&nbsp;mdtk
| SF (99%)
| (beberapa)
| rowspan=2|0+
|-
| α (1%)
| 240Cf
|-
| rowspan=3|245Fm
| rowspan=3 style="text-align:right" | 100
| rowspan=3 style="text-align:right" | 145
| rowspan=3|245,07535(21)#
| rowspan=3|4,2(13)&nbsp;dtk
| α (95,7%)
| 241Cf
| rowspan=3|1/2+#
|-
| β+ (4,2%)
| 245Es
|-
| SF (0,13%)
| (beberapa)
|-
| rowspan=4|246Fm
| rowspan=4 style="text-align:right" | 100
| rowspan=4 style="text-align:right" | 146
| rowspan=4|246,075350(17)
| rowspan=4|1,54(4)&nbsp;dtk
| α (85%)
| 242Cf
| rowspan=4|0+
|-
| β+ (10%)
| 246Es
|-
| β+, SF (10%)
| (beberapa)
|-
| SF (4,5%)
| (beberapa)
|-
| rowspan=2|247Fm
| rowspan=2 style="text-align:right" | 100
| rowspan=2 style="text-align:right" | 147
| rowspan=2|247,07695(12)#
| rowspan=2|31(1)&nbsp;dtk
| α (>50%)
| 243Cf
| rowspan=2|(7/2+)
|-
| β+ (247Es
|-
| rowspan=3|248Fm
| rowspan=3 style="text-align:right" | 100
| rowspan=3 style="text-align:right" | 148
| rowspan=3|248,077186(9)
| rowspan=3|35,1(8)&nbsp;dtk
| α (93%)
| 244Cf
| rowspan=3|0+
|-
| β+ (7%)
| 248Es
|-
| SF (0,10%)
| (beberapa)
|-
| rowspan=2|249Fm
| rowspan=2 style="text-align:right" | 100
| rowspan=2 style="text-align:right" | 149
| rowspan=2|249,078928(7)
| rowspan=2|1,6(1)&nbsp;mnt
| β+ (85%)
| 249Es
| rowspan=2|(7/2+)#
|-
| α (15%)
| 245Cf
|-
| rowspan=3|250Fm
| rowspan=3 style="text-align:right" | 100
| rowspan=3 style="text-align:right" | 150
| rowspan=3|250,079521(9)
| rowspan=3|30,4(15)&nbsp;mnt
| α (90%)
| 246Cf
| rowspan=3|0+
|-
| EC (10%)
| 250Es
|-
| SF (6,9%)
| (beberapa)
|-
| style="text-indent:1em" | 250mFm
| colspan="3" style="text-indent:2em" | 1199,2(10)&nbsp;keV
| 1,92(5)&nbsp;dtk
| IT
| 250Fm
| (8−)
|-
| rowspan=2|251Fm
| rowspan=2 style="text-align:right" | 100
| rowspan=2 style="text-align:right" | 151
| rowspan=2|251,081540(16)
| rowspan=2|5,30(8)&nbsp;jam
| β+ (98,2%)
| 251Es
| rowspan=2|(9/2−)
|-
| α (1,8%)
| 247Cf
|-
| style="text-indent:1em" | 251mFm
| colspan="3" style="text-indent:2em" | 200,09(11)&nbsp;keV
| 21,1(16)&nbsp;μdtk
|
|
| (5/2+)
|-
| rowspan=3|252Fm
| rowspan=3 style="text-align:right" | 100
| rowspan=3 style="text-align:right" | 152
| rowspan=3|252,082467(6)
| rowspan=3|25,39(4)&nbsp;jam
| α (99,99%)
| 248Cf
| rowspan=3|0+
|-
| SF (0,0023%)
| (beberapa)
|-
| β+β+ (langka)
| 252Cf
|-
| rowspan=2|253Fm
| rowspan=2 style="text-align:right" | 100
| rowspan=2 style="text-align:right" | 153
| rowspan=2|253,085185(4)
| rowspan=2|3,00(12)&nbsp;hri
| EC (88%)
| 253Es
| rowspan=2|(1/2)+
|-
| α (12%)
| 249Cf
|-
| rowspan=2|254Fm
| rowspan=2 style="text-align:right" | 100
| rowspan=2 style="text-align:right" | 154
| rowspan=2|254,0868544(30)
| rowspan=2|3,240(2)&nbsp;jam
| α (99,94%)
| 250Cf
| rowspan=2|0+
|-
| SF (0,0592%)
| (beberapa)
|-
| rowspan=2|255Fm
| rowspan=2 style="text-align:right" | 100
| rowspan=2 style="text-align:right" | 155
| rowspan=2|255,089964(5)
| rowspan=2|20,07(7)&nbsp;jam
| α
| 251Cf
| rowspan=2|7/2+
|-
| SF (2,4%)
| (beberapa)
|-
| rowspan=2|256Fm
| rowspan=2 style="text-align:right" | 100
| rowspan=2 style="text-align:right" | 156
| rowspan=2|256,091774(8)
| rowspan=2|157,6(13)&nbsp;mnt
| SF (91,9%)
| (beberapa)
| rowspan=2|0+
|-
| α (8,1%)
| 252Cf
|-
| rowspan=2|257Fm
| rowspan=2 style="text-align:right" | 100
| rowspan=2 style="text-align:right" | 157
| rowspan=2|257,095106(7)
| rowspan=2|100,5(2)&nbsp;hri
| α (99,79%)
| 253Cf
| rowspan=2|(9/2+)
|-
| SF (0,21%)
| (beberapa)
|-
| 258Fm
| style="text-align:right" | 100
| style="text-align:right" | 158
| 258,09708(22)#
| 370(14)&nbsp;μdtk
| SF
| (beberapa)
| 0+
|-
| 259Fm
| style="text-align:right" | 100
| style="text-align:right" | 159
| 259,1006(3)#
| 1,5(3)&nbsp;dtk
| SF
| (beberapa)
| 3/2+#
|-
| 260Fm
| style="text-align:right" | 100
| style="text-align:right" | 160
| 260,10281(55)#
| 4&nbsp;mdtk
| SF
| (beberapa)
| 0+

## Kronologi penemuan isotop

260Fm? tidak dikonfirmasi pada tahun 1997.

## Referensi

* Massa isotop dari:
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* Komposisi isotop dan massa atom standar dari:
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* Data waktu paruh, spin, dan isomer dipilih dari sumber-sumber berikut.
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