Nobelium is a synthetic, highly radioactive actinide named after Alfred Nobel. It shows an unusual divalent chemistry for an actinide and exists only in trace, short-lived quantities produced in particle accelerators.
Nobelium (No) is a man-made actinide with atomic number 102, located in period 7 of the f-block between mendelevium (Md) and lawrencium (Lr). It was named in honor of Alfred Nobel.
Unlike most actinides (which prefer the +3 state in water), nobelium is dominated by the +2 oxidation state (No(II)) in aqueous solution. This reflects its near-closed 5f shell behavior, giving it chemistry that in some ways resembles divalent lanthanides like europium and ytterbium.
A commonly cited ground-state configuration is [Rn] 5f14 7s2. The filled 5f14 subshell helps stabilize No(II) and explains the relative weakness of the +3 state compared with neighboring actinides.
Nobelium is created atom-by-atom in heavy-ion fusion reactions using particle accelerators, typically by bombarding curium or californium targets with carbon or calcium ions, then isolating atoms via on-line radiochemical or kinematic separation:
\(^{244\text{–}248}\mathrm{Cm} (^{12\text{–}13}\mathrm{C},\,x n)\,^{256\text{–}259}\mathrm{No}\)
Short-lived isotopes such as No-252, No-254, No-255, No-257, and No-259 are known. Most decay by alpha emission and/or spontaneous fission, with half-lives ranging from seconds to minutes (some to hours), limiting bulk studies.
No(II) is dominant in water; No(III) can be accessed under oxidizing conditions but is less stable. In solution, chemists refer to hydrated cations like:
The preference for +2 allows selective redox-based separations from neighboring trivalent actinides.
They exploit the No(II)/No(III) redox switch using rapid ion-exchange or extraction chromatography at tracer levels. Identification relies on alpha-decay chains, time-correlated detection, and characteristic energies rather than macroscopic properties.
Yes. Production routes are themselves notable heavy-ion fusion reactions. A stylized example is:
\(^{248}\mathrm{Cm} (^{12}\mathrm{C},\,4n)\,^{256}\mathrm{No}\)
After formation, nobelium isotopes typically undergo \(\alpha\)-decay:
\(^{257}\mathrm{No} \;\to\; ^{253}\mathrm{Fm} + \alpha\)
Outside of fundamental research (nuclear structure, actinide chemistry, rapid separations), there are no routine applications. Production is extremely limited, and short half-lives preclude bulk use.
Yes. Like other late actinides, nobelium is a radiotoxic heavy metal. Although handled in atom-to-picogram amounts, work requires hot-cell or glove-box techniques, HEPA-filtered ventilation, remote manipulation tools, dosimetry, and compliant radioactive-waste procedures.