Symbol Name Atomic Number Atomic Weight Group Number
Uun Ununnilium 110 269 10


Standard State: Presumably a solid at 298 K
Color: Unknown, but probably metallic and silvery white or gray in appearance

Ununnilium, is a synthetic element that is not present in the environment at all. The interested reader should consult the on-line version of The Wonderful World of Atoms and Nuclei for a fascinating insight into research on "super-heavy" atoms. Chemically, the element 110 is in the same Group as nickel, palladium, and platinum (Group 10). Unlike these lighter atoms, element 110 decays after a small fraction of a thousandth of a second into lighter elements by emitting a-particles which are the nuclei of helium atoms.

Only a few atoms of element 110 have ever been made, initially through a nuclear reaction involving fusion of an isotope of lead, Pb, with one of nickel, Ni.