Atomic Symbol Rg
Atomic Number 111
Atomic Weight 272
presumably a solid at 298 K
Color unknown, but probably metallic and silvery white or grey in appearance

Roentgenium is a synthetic element that is not present in the environment. Isolation of an observable quantity of roentgenium has never been achieved, and thus roentgenium has no known uses. The reactivity of roentgenium is unknown, but is assumed to be similar to gold and silver.

Roentgenium was first synthesized on December 8, 1994 at the Gesellschaft für Schwerionenforschung a.k.a the Institute for Heavy Ion Research a.k.a. GSI in Darmstadt, Germany, producing three atoms in an 18 day experiment using their heavy ion accelerator UNILAC, via
Bismuth(209) + Nickel(64) = Roentgenium(272) + 1 neutron

Originally named unununium, element 111 was renamed roentgenium on November 1, 2004, in honor of Wilhelm Roentgen. It is also sometimes referred to as eka-gold.

There are three known isotopes of roentgenium
280Rg with a half life of 3.6 seconds
279Rg with a half life of 170 milliseconds
272Rg with a half life of 1.5 milliseconds

darmstadtium <-- roentgenium --> Copernicium