Fermium
About Fermium
Fermium was discovered in 1952 by a team of Berkeley researchers led by Albert Ghiorso while analyzing coral contaminated by the top-secret Ivy Mike nuclear test, of but their discovery was kept secret until 1955 because of Cold War tensions. Fermium was named for the recently deceased Enrico Fermi and his invaluable contributions to the field of nuclear physics.
Little is known about the properties of fermium because only tiny amounts have ever been produced; after their initial experiement, Ghiorso's team was again successful in producing both fermium and einsteinium via the bombardment of plutonium-239. It is a highly radioactive transuranic actinide with a very short half-life. There are no uses for it outside of scientific research.
Fermium Properties
Fermium is a Block F, Group 3, Period 7 element. The number of electrons in each of fermium's shells is 2, 8, 18, 32, 30, 8, 2 and its electron configuration is [Rn] 5f12 7s2. The fermium atom has a Van der Waals radius of 245 pm. In its elemental form, fermium's CAS number is 7440-72-4. Fermium is a synthetic element that is produced by the bombardment of lighter actinides with neutrons in a nuclear reactor. Fermium was discovered at the Lawrence Berkeley National Laboratory in 1952. It was named after Enrico Fermi, Professor of Theoretical Physics at the University of Rome. Fermi was a Nobel Prize winner whose work lead to the discovery of slow neutrons which then resulted in the discovery of nuclear fission and the production of elements lying beyond those included on the periodic table of 1938. Fermium was the eighth transuranic element of the actinide series to be discovered.
Fermium information, including technical data, safety data and its properties, research, applications and other useful facts are discussed below. Scientific facts such as the atomic structure, ionization energy, abundance on Earth, conductivity and thermal properties are included.
General Properties
Symbol: | Fm |
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Atomic Number: | 100 |
Atomic Weight: | 257 |
Element Category: | Actinide |
Group, Period, Block: | n/a, 7, f |
Color: | unknown (presumably metallic/ silvery white/ gray) |
Other Names: | Fermio |
Physical Properties
Melting Point: | 1527 °C, 2780.6 °F, 1800.15 K |
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Boiling Point: | N/A |
Density: | N/A |
Liquid Density @ Melting Point: | N/A |
Density @ 20°C: | 8.84 g/cm3 |
Density of Solid: | N/A |
Specific Heat: | N/A |
Superconductivity Temperature: | N/A |
Triple Point: | N/A |
Critical Point: | N/A |
Heat of Fusion (kJ·mol-1): | N/A |
Heat of Vaporization (kJ·mol-1): | N/A |
Heat of Atomization (kJ·mol-1): | 141 |
Thermal Conductivity: | N/A |
Thermal Expansion: | N/A |
Electrical Resistivity: | N/A |
Tensile Strength: | N/A |
Molar Heat Capacity: | N/A |
Young's Modulus: | N/A |
Shear Modulus: | N/A |
Bulk Modulus: | N/A |
Poisson Ratio: | N/A |
Mohs Hardness: | N/A |
Vickers Hardness: | N/A |
Brinell Hardness: | N/A |
Speed of Sound: | N/A |
Pauling Electronegativity: | 1.3 |
Sanderson Electronegativity: | N/A |
Allred Rochow Electronegativity: | 1.2 |
Mulliken-Jaffe Electronegativity: | N/A |
Allen Electronegativity: | N/A |
Pauling Electropositivity: | 2.7 |
Reflectivity (%): | N/A |
Refractive Index: | N/A |
Chemical Properties
Electrons: | 100 |
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Protons: | 100 |
Neutrons: | 157 |
Electron Configuration: | [Rn] 5f12 7s2 |
Atomic Radius: | N/A |
Atomic Radius, non-bonded (Å): | 2.45 |
Covalent Radius: | N/A |
Covalent Radius (Å): | 1.67 |
Van der Waals Radius: | 245 pm |
Oxidation States: | 2, 3 |
Phase: | Solid |
Crystal Structure: | N/A |
Magnetic Ordering: | N/A |
Electron Affinity (kJ·mol-1) | Unknown |
1st Ionization Energy: | 627 kJ·mol-1 (estimated) |
2nd Ionization Energy: | N/A |
3rd Ionization Energy: | N/A |
Identifiers
CAS Number: | 7440-72-4 |
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EC Number: | N/A |
MDL Number: | N/A |
Beilstein Number: | N/A |
SMILES Identifier: | [Fm] |
InChI Identifier: | InChI=1S/Fm |
InChI Key: | MIORUQGGZCBUGO-UHFFFAOYSA-N |
PubChem CID: | 23998 |
ChemSpider ID: | 22434 |
Abundance
Earth - Total: | N/A |
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Mercury - Total: | N/A |
Venus - Total: | N/A |
Earth - Seawater (Oceans), ppb by weight: | N/A |
Earth - Seawater (Oceans), ppb by atoms: | N/A |
Earth - Crust (Crustal Rocks), ppb by weight: | N/A |
Earth - Crust (Crustal Rocks), ppb by atoms: | N/A |
Sun - Total, ppb by weight: | N/A |
Sun - Total, ppb by atoms: | N/A |
Stream, ppb by weight: | N/A |
Stream, ppb by atoms: | N/A |
Meterorite (Carbonaceous), ppb by weight: | N/A |
Meterorite (Carbonaceous), ppb by atoms: | N/A |
Typical Human Body, ppb by weight: | N/A |
Typical Human Body, ppb by atom: | N/A |
Universe, ppb by weight: | N/A |
Universe, ppb by atom: | N/A |
History
Discovered By: | Lawrence Berkeley Nat'l Laboratory |
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Discovery Date: | 1952 |
First Isolation: | N/A |
Fermium Isotopes
Fermium is an artificial element. It has no stable isotopes.
Nuclide | Isotopic Mass | Half-Life | Mode of Decay | Nuclear Spin | Magnetic Moment | Binding Energy (MeV) | Natural Abundance (% by atom) |
---|---|---|---|---|---|---|---|
241Fm | 241.07421(32)# | 730(60) µs | SF; a to 237Cf | 5/2#+ | N/A | N/A | - |
242Fm | 242.07343(43)# | 0.8(2) ms | SF; a to 238Cf | 0+ | N/A | 1806.625 | - |
243Fm | 243.07447(23)# | 231(9) ms | a to 239Cf; SF; ß+to 243Es | 7/2-# | N/A | 1813.69104 | - |
244Fm | 244.07404(22)# | 3.12(8) ms | a to 240Cf; ß+to 244Es; SF | 0+ | N/A | 1822.165039 | - |
245Fm | 245.07535(21)# | 4.2(13) s | a to 241Cf; ß+to 245Es; SF | 1/2+# | N/A | 1829.026978 | - |
246Fm | 246.075350(17) | 1.54(4) s | a to 242Cf; ß+to 246Es; SF | 0+ | N/A | 1837.185669 | - |
247Fm | 247.07695(12)# | 31(1) s | a to 243Cf; ß+to 247Es | (7/2+) | N/A | 1843.824951 | - |
248Fm | 248.077186(9) | 35.1(8) s | ß+to 248Es; a to 244Cf; SF | 0+ | N/A | 1851.555908 | - |
249Fm | 249.078928(7) | 1.6(1) min | ß+to 249Es; a to 245Cf; SF | (7/2+)# | N/A | 1857.912964 | - |
250Fm | 250.079521(9) | 30.4(15) min | a to 246Cf; EC to 250Es; SF | 0+ | N/A | 1865.527832 | - |
251Fm | 251.081540(16) | 5.30(8) h | EC to 251Es; a to 247Cf | (9/2-) | N/A | 1871.687988 | - |
252Fm | 252.082467(6) | 25.39(4) h | a to 248Cf; SF | 0+ | N/A | 1878.927002 | - |
253Fm | 253.085185(4) | 3.00(12) d | EC to 253Es; a to 249Cf | (1/2)+ | N/A | 1884.46814 | - |
254Fm | 254.0868544(30) | 3.240(2) h | a to 250Cf; SF | 0+ | N/A | 1890.982422 | - |
255Fm | 255.089964(5) | 20.07(7) h | a to 251Cf; SF | 7/2+ | N/A | 1896.159058 | - |
256Fm | 256.091774(8) | 157.6(13) min | a to 252Cf; SF | 0+ | N/A | 1902.543335 | - |
257Fm | 257.095106(7) | 100.5(2) d | a to 253Cf; SF | (9/2+) | N/A | 1907.510864 | - |
258Fm | 258.09708(22)# | 370(14) µs | SF | 0+ | N/A | 1913.746948 | - |
259Fm | 259.1006(3)# | 1.5(3) s | SF | 3/2+# | N/A | 1918.540039 | - |
260Fm | 260.10281(55)# | 1# min | N/A | 0+ | N/A | N/A | - |