fermium

Fermium Fermium. A man-made radioactive actinide with atomic symbol Fm, atomic number 100, and atomic weight 257. Its known isotopes range from 244-254 and 256-258. Its valence can be +2 or +3. Like einsteinium, it was discovered in 1952 in the debris from a thermonuclear explosion.

[symbol for fermium.

[1. 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.

Molecular Formula: Fm

InChI: InChI=1/Fm

InChIKey: InChIKey=MIORUQGGZCBUGO-UHFFFAOYAE
SMILES: [Fm]

CAS number 7440-72-4

Names:
    FERMIUM
    fermium
    Fm
    100Fm

Registries:
    PubChem CID 23998
    CAS 7440-72-4 (from NIST)
    ChEBI 33394
    PubChem ID 10534562
    WebElements Fm