Roentgenium (Rg)


  • Symbol: Rg
  • Atomic Number: 111
  • Atomic Weight: [282]
  • Element Classification: Transition Metal
  • Discovered By: Society for Heavy Ion Research (GSI) in Darmstadt, Germany
  • Discovery Date: 1994
  • Name Origin: Named after Wilhelm Conrad Röntgen, the discoverer of X-rays
  • Density(g/cc): Estimated to be around 28.7 (predicted)
  • Melting Point: Unknown
  • Boiling Point: Unknown
  • Appearance: Presumed to be a solid under standard conditions, but its actual appearance is unknown due to its extreme radioactivity and the minute amounts produced
  • Atomic Radius(pm): Estimated


Roentgenium was discovered in 1994 by a team at the Society for Heavy Ion Research (GSI) in Darmstadt, Germany. The discovery was made by bombarding bismuth-209 with nickel-64 ions, leading to the synthesis of roentgenium-272. The element was named in honor of Wilhelm Conrad Röntgen, the German physicist who discovered X-rays in 1895 and was awarded the first Nobel Prize in Physics in 1901.

Relation to Other Elements

Roentgenium is expected to be part of group 11 of the periodic table, which includes copper, silver, and gold, making it a transition metal. Due to its position in the periodic table, roentgenium is anticipated to share some properties with gold, its lighter homologue. However, the chemical and physical properties of roentgenium are largely unknown and based on theoretical predictions or limited experimental data, as the element’s short half-life and the small amounts produced make detailed studies challenging.

Natural Occurrence

Roentgenium does not occur naturally and is produced synthetically in particle accelerators through specific nuclear reactions.


The applications for roentgenium are currently limited to scientific research due to its rarity, short half-life, and radioactivity:

  • Scientific Research: Roentgenium is used in research to investigate the properties of superheavy elements and to understand better the limits of the periodic table. Studies involving roentgenium aim to gain insights into its atomic structure, chemical behavior, and how relativistic effects influence the properties of heavy elements.

The discovery of roentgenium added to the growing list of superheavy elements, pushing further the boundaries of nuclear chemistry and atomic physics. While practical applications are yet to be realized, the ongoing study of roentgenium and other superheavy elements continues to offer valuable insights into the fundamental principles governing the behavior of matter at the atomic level.

Darmstadtium (Ds)

Copernicium (Cn)