Fermium

einsteinium ← fermium → mendelevium Er ↑ Fm ↓ –

Atomic properties Atomic number 100 Electron configuration [Rn] 5f12 6s2 Physical properties Melting point 1125 K (850 °C) est. Chemical properties Electronegativity 1.3 (Pauling) est. Ionization energy 6.50 eV 627 kJ mol−1 Atomic radii Metallic radius 196 pm est. Ionic radius 92 pm (Fm3+) est. Thermodynamic properties Enthalpy change of atomization 142(13) kJ mol−1 Entropy change of atomization 98(13) J K−1 mol−1 Miscellaneous CAS number 7440-72-4 Where appropriate, and unless otherwise stated, data are given for 100 kPa (1 bar) and 298.15 K (25 °C).

Fermium (symbol: Fm) is a synthetic chemical element and a member of the actinoid series. It is the heaviest element than can be formed by neutron bombardment of lighter elements, and hence the last element that can be prepared in macroscopic quantities.

Notes and references

Further reading

• Hulet, E. K. Chemistry of the Heaviest Actinides: Fermium, Mendelevium, Nobelium, and Lawrencium. In Lanthanide and Actinide Chemistry and Spectroscopy; Edelstein, Norman M., Ed.; American Chemical Society: Washington, D.C.; Chapter 12, pp 239–63. ACS Symposium Series, Vol. 131. ISBN 9780841205680. DOI: 10.1021/bk-1980-0131.ch012.
• Silva, Robert J. Fermium, Mendelevium, Nobelium, and Lawrencium. In The Chemistry of the Actinide and Transactinide Elements, 3rd ed.; Morss, Lester R.; Edelstein, Norman M.; Fuger, Jean, Eds.; Springer: Dordrecht, 2006; Vol. 3, Chapter 13, pp 1621–51. doi:10.1007/1-4020-3598-5_13, <http://radchem.nevada.edu/classes/rdch710/files/Fm%20to%20Lr.pdf>

External links

• WebElements