EnvironmentalChemistry.com
Environmental, Chemistry & Hazardous Materials News, Careers & Resources

Periodic Table of Elements

Fm - Fermium

Fermium Menu

Nuclides / Isotopes

Nuc-
lide
Atomic
Mass
NNAbun
%
SpinHalf LifeDMDTBR
%
Decay
Energy
(MeV)
Fm242242.073142Syn0+0.8msSF   
Fm243243.075143Syn 0.18sαCf239<=1008.690
 0.18sSF <=0.368.690
Fm244244.074144Syn0+3.3msSF <=100 
Fm245245.075145Syn 4.2sαCf241<=1008.440
 4.2sSF <=0.11 
Fm246246.0753146Syn0+1.1sαCf242928.374
 1.1sSF 8 
 1.1s εEs246<=12.160
Fm247247.077147Syn 35sαCf243>=508.190
 35s εEs247<=508.190
Fm248248.0772148Syn0+36sαCf244998.002
 36s εEs248~11.600
 36sSF ~0.05 
Fm249249.079149Syn7/2+2.6m εEs249~852.440
 2.6mαCf245~157.810
 2.6mα   
 2.6m ε   
Fm250250.0795150Syn0+30mαCf246>907.557
 30m εEs250<100.800
 30mSF ~0.00060.800
meta state 1.000MeVSyn 1.8sITFm250>801.000
 1.8sSF  1.000
Fm251251.0816151Syn9/2-5.3h εEs25198.21.474
 5.3hαCf2471.87.425
Fm252252.0825152Syn0+25.39hSF 0.0023 
 25.39hαCf248 7.153
Fm253253.0852153Syn1/2+3d εEs253880.333
 3dαCf249127.197
Fm254254.0869154Syn0+3.24hαCf25099.947.307
 3.24hSF 0.06 
Fm255255.09155Syn7/2+20.07hSF 0.00002 
 20.07hαCf251 7.241
Fm256256.0918156Syn0+157.6mSF 91.9 
 157.6mαCf2528.17.027
Fm257257.0951157Syn9/2+100.5dαCf25399.796.864
 100.5dSF 0.21 
Fm258258.097158Syn0+370usSF   
Fm259259.101159Syn 1.5sSF   
Fm260 160Syn0+~4ms    
NuclidePotential Parent Nuclides
Fm242None known
Fm243None known
Fm244None known
Fm245None known
Fm246No250 (Syn)
Fm247No251 (Syn)
Fm248Md248 (Syn) No252 (Syn)
Fm249Md249 (Syn) No253 (Syn)
Fm250Fm250m (Syn) Md250 (Syn) No254 (Syn)
meta state 1.000MeVNone known
Fm251Md251 (Syn) No255 (Syn)
Fm252Es252 (Syn) Md252 (Syn) No256 (Syn)
Fm253Md253 (Syn) No257 (Syn)
Fm254Es254 (Syn) Es254m (Syn) Md254 (Syn) No258 (Syn)
Fm255Es255 (Syn) Md255 (Syn) No259 (Syn)
Fm256Es256 (Syn) Es256m (Syn) Md256 (Syn)
Fm257Md257 (Syn)
Fm258Md258 (Syn)
Fm259None known
Fm260Md260 (Syn)

Key:

  • NN = Number of Neutrons
  • Abun % = Natural Abundance (as a percentage)
  • Syn = Synthetic Nuclide (does not occur in nature)
  • DM = Decay Mode
    α = Alpha emission
    β- = Beta emission
    β- β- = Double beta decay
    β+ = Positron emission
    ε = Electron Capture
    IT = Isomeric Transition
    N = Neutron emission
    P = Proton emission
    SF = Spontaneous Fission
  • DT = Decays To
  • BR % = Branch Ratio (as a percentage)

Fermium Menu

Related Resources

Citing this page

If you need to cite this page, you can copy this text:

Linking to this page

If you would like to link to this page from your website, blog, etc., copy and paste this link code (in red) and modify it to suit your needs:

NOTICE: While linking to articles is encouraged, OUR ARTICLES MAY NOT BE COPIED TO OR REPUBLISHED ON ANOTHER WEBSITE UNDER ANY CIRCUMSTANCES.

PLEASE, if you like an article we published simply link to it on our website do not republish it.

Career Listings

Featured Articles

Latest Headlines

Go Green

Environmental Issues

Chemistry

Hazardous Materials

Educators

This website is a great teaching resource!! Pages are printer friendly, making them easy to use as classroom handouts.

Notes about using this site in the classroom.

Image map of the periodic table of elements Click here for main periodic table or move mouse to desired element.1 Hydrogen2 Helium3 Lithium4 Beryllium5 Boron6 Carbon7 Nitrogen8 Oxygen9 Fluorine10 Neon11 Sodium12 Magnesium13 Aluminum14 Silicon15 Phosphorus16 Sulfur17 Chlorine18 Argon19 Potassium20 Calcium21 Scandium22 Titanium23 Vandium24 Chromium25 Manganese26 Iron27 Cobalt28 Nickel29 Copper30 Zinc31 Gallium32 Germanium33 Arsenic34 Selenium35 Bromine36 Krypton37 Rubidium38 Strontium39 Yttrium40 Zirconium41 Niobium42 Molybdenum43 Technetium44 Ruthenium45 Rhodium46 Palladium47 Silver48 Cadmium49 Indium50 Tin51 Atimony52 Tellurium53 Iodine54 Xenon55 Cesium56 Barium57 Lathanum72 Hafnium73 Tantalum74 Tungsten75 Rhenium76 Osmium77 Iridium78 Platinum79 Gold80 Mercury81 Thallium82 Lead83 Bismuth84 Polonium85 Astatine86 Radon87 Francium88 Radium89 Actinium104 Rutherfordium105 Dubnium106 Seaborgium107 Bohrium108 Hassium109 Meitnerium110 Darmstadtium111 Roentgenium58 Cerium59 Praseodymium60 Neodymium61 Promethium62 Samarium63 Europium64 Gadolinium65 Terbium66 Dysprosium67 Holmium68 Erbium69 Thulium70 Ytterbium71 Lutetium90 Thorium91 Protactinum92 Uranium93 Neptunium94 Plutonium95 Americium96 Curium97 Berkelium98 Californium99 Einsteinium100 Fermium101 Mendelevium102 Nobelium103 Larencium