Seaborgium is a synthetic element whose most stable isotope 271Sg has a half-life of 1.9 minutes. A new isotope 269Sg has a potentially slightly longer half-life (ca. 2.1 min) based on the observation of a single decay. Chemistry experiments with seaborgium have firmly placed it in group 6 as a heavier homologue to tungsten. is a chemical element with the symbol Sg and atomic number 106. Sg + O2 + 2 HCl → SgO2Cl2 + H2