Fermium Isotopic Data
Isotope |
Isotopic Mass amu |
% Abundance |
T1/2 |
T1/2 Units |
Mass Excess KeV |
Binding Energy Per Nucleon KeV |
Decay Mode |
Branching Ratio |
242Fm | 242.07343 (43) |
| 800 | us | 68,400 (400) | 7,465 (2) | SF | ? |
243Fm | 243.07435 (23) |
| 210 | ms | 69,260 (220) | 7,464 (1) | A | 60 40 |
244Fm | 244.07408 (30) |
| 3.3 | ms | 69,010 (280) | 7,468 (1) | SF~100 |
|
245Fm | 245.07539 (30) |
| 4.2 | s | 70,220 (280) | 7,465 (1) | A | ? |
246Fm | 246.075299 (42) |
| 1.1 | s | 70,141 (39) | 7,468.2 (1.6) | A | ? |
247Fm | 247.07685 (15) |
| 35 | s | 71,580 (140) | 7,465 (1) | A GE 50 |
|
248Fm | 248.077195 (13) |
| 36 | s | 71,906 (12) | 7,465.91 (4.7) | A | 93 7 |
249Fm | 249.07903 (11) |
| 2.6 | m | 73,620 (100) | 7,461 (0) | B+ ? |
|
250Fm | 250.079521 (13) |
| 30 | m | 74,074 (12) | 7,462.08 (4.8) | A>90 |
|
251Fm | 251.0815750 (90) |
| 5.3 | h | 75,986.6 (8.4) | 7,456.89 (3.3) | B+ | 98.20 13 |
252Fm | 252.0824669 (61) |
| 25.39 | h | 76,817.4 (5.7) | 7,456.03 (2.3) | A~100 |
|
253Fm | 253.0851852 (40) |
| 3 | d | 79,349.5 (3.7) | 7,448.46 (1.5) | EC | 88 1 |
254Fm | 254.0868542 (30) |
| 3.24 | h | 80,904.2 (2.8) | 7,444.79 (1.1) | A~100 |
|
255Fm | 255.0899622 (52) |
| 20.07 | h | 83,799.3 (4.8) | 7,435.89 (1.9) | A | 100 |
256Fm | 256.0917731 (77) |
| 157.6 | m | 85,486.1 (7.2) | 7,431.78 (2.8) | SF | 91.9 3 |
257Fm | 257.0951047 (68) |
| 100.5 | d | 88,589.5 (6.3) | 7,422.20 (2.5) | A~100 |
|
258Fm | 258.09708 (22) |
| 370 | us | 90,430 (200) | 7,418 (1) | SF~100 |
|
259Fm | 259.10060 (30) |
| 1.5 | s | 93,700 (280) | 7,407 (1) | SF | 100 |
260Fm | 260.10268 (54) |
| 1 | m | 95,640 (500) | 7,403 (2) | SF ? |
|
247mFm | 247.07685 (15) |
| 9.2 | s | 71,580 (140) | 7,465 (1) | A~100 | |
250mFm | 250.079521 (13) |
| 1.8 | s | 74,074 (12) | 7,462.08 (4.8) | IT>80 |
|
251mFm | 251.0815750 (90) |
| 15.2 | us | 75,986.6 (8.4) | 7,456.89 (3.3) | IT | 100 |
247m1Fm | 247.07685 (15) |
|
|
| 71,580 (140) | 7,465 (1) | 0 |
|
255mFm | 255.0899622 (52) |
|
|
| 83,799.3 (4.8) | 7,435.89 (1.9) | 0 |
|
247m2Fm | 247.07685 (15) |
|
|
| 71,580 (140) | 7,465 (1) | 0 |
|
Data Source: ENSDF March 2005
©Radiochemistry Society 2005