Seaborgium is a synthetic, highly radioactive transactinide metal in group 6. It was first reported in 1974 and later confirmed by teams in Dubna (JINR) and Berkeley–Livermore. The element is named after nuclear chemist Glenn T. Seaborg. All isotopes are short-lived and produced only in particle accelerators.
Seaborgium (Sg) is a synthetic transactinide element with atomic number 106. It belongs to Group 6 (the chromium–molybdenum–tungsten family) and lies in period 7. Because it does not occur in nature, it is produced atom-by-atom in particle accelerators.
It honors Glenn T. Seaborg, a Nobel Prize–winning nuclear chemist who co-discovered several transuranium elements and pioneered actinide chemistry. The name reflects the element’s roots in heavy-element synthesis and radiochemical methods.
Seaborgium isotopes are made in fusion–evaporation reactions by accelerating medium-mass ions into heavy actinide targets. Stylized examples include:
\(^{248}\mathrm{Cm}(^{18}\mathrm{O},\,xn)\,^{266-x}\mathrm{Sg}\)
\(^{249}\mathrm{Cf}(^{18}\mathrm{O},\,xn)\,^{267-x}\mathrm{Sg}\)
After formation, the hot compound nucleus emits n neutrons (\(xn\)) to reach a specific Sg isotope.
Freshly formed atoms recoil from the target into a separator and are implanted in position-sensitive detectors. They are identified by time-correlated decay chains (mainly \(\alpha\) decay and sometimes spontaneous fission) with characteristic energies:
\(^{A}_{106}\mathrm{Sg} \;\to\; ^{A-4}_{104}\mathrm{Rf} + \alpha \;\to\; \cdots\)
By analogy with molybdenum (Mo) and tungsten (W), Sg is expected to favor the +6 oxidation state, with access to +5 and +4 in suitable conditions. Gas-phase, atom-at-a-time studies indicate formation of halides and oxychlorides (e.g., volatile SgO2Cl2) akin to Mo/W chemistry under chlorinating/oxidizing conditions.
Relativistic calculations and periodic trends support a ground-state configuration close to [Rn] 5f14 6d4 7s2. The participation of 6d and 7s electrons (with relativistic effects) underpins its Group-6-like chemistry.
All known isotopes are short-lived, typically with half-lives from milliseconds to a few minutes, depending on the mass number. Dominant decay modes are alpha decay and spontaneous fission:
\(^{A}\mathrm{Sg} \;\xrightarrow{\alpha}\; ^{A-4}\mathrm{Rf} + \alpha\)
Only a few atoms are made per experiment and they decay quickly. That makes it impossible to prepare macroscopic samples to measure properties like density, melting point, or crystal structure. Most insights come from single-atom chromatography and gas-phase thermochromatography.
Available evidence shows Sg follows Group-6 trends: formation of high-valent oxychlorides/oxofluorides and comparable volatility patterns to W/Mo species under similar conditions. However, relativistic effects in the 6d series may cause subtle deviations from simple periodic extrapolations.
Yes. One illustrative pair is:
\(^{248}\mathrm{Cm}(^{18}\mathrm{O},\,4n)\,^{262}\mathrm{Sg}\)
\(^{262}\mathrm{Sg} \;\to\; ^{258}\mathrm{Rf} + \alpha\)