Periodic Table/Fermium/²⁴⁹Fm

← 248Fm250Fm →

²⁴⁹Fm

Fermium-249

Radioactive· Half-life: 1.60 min

Nuclear Propertiesbinding energy · spin-parity · abundance

Protons (Z)

100

Neutrons (N)

149

Mass Number (A)

249

Atomic Mass

249.078926AMU

Spin / Parity

7/2+

Binding E/A

7.257keV

Natural Abundance

Trace / None

Half-life

1.60 min

Decay Modesoverview · half-life · α · β⁻ · β⁺

β⁺

α

33.0%

Decay Chain

²⁴⁹FmFermium1.60 min

α33.0%

β⁺²⁴⁹Es

²⁴⁵CfCalifornium45.0 min

β⁺64.7%

α²⁴¹Cm35.3%

²⁴⁵BkBerkelium4.95 d

EC99.9%

α²⁴¹Am0.12%

²⁴⁵CmCurium8.25 ky

α100.0%

²⁴¹PuPlutonium14.3 y

β⁻100.0%

α²³⁷U0.00%

²⁴¹AmAmericium433 y

α100.0%

²³⁷NpNeptunium2.14 My

α100.0%

30Mg²⁰⁷Tl4.00%

²³³PaProtactinium27.0 d

β⁻100.0%

²³³UUranium159 ky

α100.0%

24Ne²⁰⁹Pb7.20%

28Mg²⁰⁵Hg1.30%

²²⁹ThThorium7.92 ky

α100.0%

²²⁵RaRadium14.8 d

β⁻100.0%

²²⁵AcActinium9.92 d

α100.0%

¹⁴C²¹¹Bi5.30%

²²¹FrFrancium4.80 min

α100.0%

¹⁴C²⁰⁷Tl8.80%

β⁻²²¹Ra0.00%

²¹⁷AtAstatine32.6 ms

α100.0%

β⁻²¹⁷Rn0.01%

²¹³BiBismuth45.6 min

β⁻97.9%

α²⁰⁹Tl2.09%

²¹³PoPolonium3.71 μs

α100.0%

²⁰⁹PbLead3.23 h

β⁻100.0%

²⁰⁹BiBismuth20100000000 Gy

α100.0%

²⁰⁵TlThalliumSTABLE

19-step decay chain → stable · Primary path shown · branching ratios indicated

Other Isotopes of Fermium

241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260

← Back to FermiumData: IAEA NDS · ENSDF