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Pronunciation: fer'me-um

Definition: Radioactive element, artificially prepared in 1955, atomic no. 100, atomic wt. 257.095; 257Fm has the longest known half-life (100.5 days) of this transuranium element.

[Enrico Fermi]

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© Copyright 2018 Wolters Kluwer. All Rights Reserved. Review date: Sep 19, 2016.