Seaborgium is a metal in Group VIB and the 7th period. It is a synthetic element; none occurs naturally on earth.

The element was discovered almost simultaneously in 1974 by Ghiorso, et al., at the University of California - Berkeley and by Flerov and Organessian at the Joint Institute for Nuclear Research at Dubna, Russia. It was named for Glenn T. Seaborg, an American chemist and nuclear physicist.

Sg is synthetic, just as all other elements beyond U. It was first made by bombarding ²⁴⁹Cf with heavy ¹⁸O ions.

²⁶³Sg has a half-life of 0.9 seconds (as an alpha emitter).

Little is known about the chemistry of Seaborgium. It is expected to have properties similar to Tungsten.