111
Rg
Roentgenium

Roentgenium

Element 111 • Transition Metal
Atomic Mass 280.000000
Electron Config Unknown
Group/Period 11/7

Table of Contents

Physical Properties Special Properties Applications Common Uses Natural Occurrence Discovery Safety Information Frequently Asked Questions

Physical Properties

MEASURED
Atomic Mass
280.000000 u
Ionization Energy
10.40 kJ/mol

Special Properties

CLASSIFIED
RADIOACTIVE This element emits radiation

Applications

CATALOGUED
Roentgenium, being an extremely short-lived synthetic superheavy element with a half-life measured in seconds, has no practical applications outside of fundamental nuclear physics research and theoretical studies exploring the limits of atomic structure and nuclear stability. The element serves exclusively to advance scientific understanding of superheavy nuclei and provide crucial experimental data for testing theoretical predictions about the proposed island of stability where certain superheavy elements might have longer half-lives. Research with Roentgenium contributes to validating sophisticated nuclear shell models and understanding how protons and neutrons organize themselves in very heavy atomic nuclei at the extremes of nuclear physics. The element is used as an important testing ground for advanced theoretical models that attempt to predict the chemical and physical properties of superheavy elements through complex relativistic quantum mechanical calculations. Roentgenium research helps scientists understand how relativistic effects profoundly influence atomic behavior and chemical properties as elements become increasingly heavy and electrons approach significant fractions of light speed. The experimental techniques and instrumentation developed for creating and detecting Roentgenium have significantly advanced nuclear physics technology and contributed to major improvements in particle accelerator systems and ultra-sensitive detection equipment. Studies of Roentgenium provide invaluable data for understanding stellar nucleosynthesis processes and how the heaviest elements in the universe are formed during extreme astrophysical events such as neutron star collisions and supernovae. The element's research contributes substantially to training the next generation of nuclear physicists and developing cutting-edge experimental methodologies for studying rare nuclear phenomena at the absolute frontiers of current scientific capability. While Roentgenium itself has no practical applications, the fundamental research it enables significantly advances our understanding of nuclear processes that underlie many important technologies in nuclear medicine, nuclear power generation, and advanced materials science. The extensive international collaborative efforts required for Roentgenium research promote scientific cooperation and facilitate knowledge sharing among the global nuclear physics research community. Future discoveries of longer-lived Roentgenium isotopes or related superheavy elements might potentially reveal unique properties with applications in advanced scientific instrumentation or specialized technological fields.

Common Uses

INDEXED
Roentgenium has absolutely no applications in everyday life, industry, commerce, or practical technology due to its extremely short half-life of approximately 26 seconds and the fact that only individual atoms can be produced at the most advanced particle accelerator facilities in the world. The element is used exclusively in cutting-edge nuclear physics research at a handful of major international laboratories equipped with the most sophisticated heavy-ion accelerators and detection systems available to science. Research institutions study Roentgenium to explore fundamental questions about the theoretical limits of atomic structure, nuclear stability, and the maximum number of protons that can be contained within a single atomic nucleus. Nuclear physicists use Roentgenium as a crucial benchmark for testing and validating the most advanced theoretical models that predict the behavior, properties, and chemical characteristics of superheavy elements at the extremes of the periodic table. The element serves as an essential experimental testing ground for computational chemistry methods that attempt to predict chemical properties and atomic behavior through sophisticated relativistic quantum mechanical calculations rather than direct experimental measurement. Educational programs in advanced nuclear physics use Roentgenium as a premier example of cutting-edge research into the fundamental nature of matter and the ongoing scientific quest to understand atomic structure at its absolute limits. Scientific databases, reference materials, and research publications maintain comprehensive records of Roentgenium's properties to ensure complete documentation of all known chemical elements, including those existing only briefly under highly specialized laboratory conditions. International scientific collaborations study Roentgenium to advance global understanding of superheavy element physics and foster unprecedented levels of knowledge sharing in nuclear research at the frontiers of human scientific capability. The element's study contributes significantly to developing revolutionary new experimental techniques and instrumentation for detecting and analyzing extremely rare nuclear events and ephemeral nuclear species. While Roentgenium cannot be used in any conceivable practical applications, research into its properties advances fundamental science that underlies nuclear technologies used in medical imaging, cancer treatment, nuclear power generation, and advanced materials research. The highly sophisticated methodologies developed specifically for Roentgenium research contribute to major breakthroughs in particle physics instrumentation, nuclear analysis techniques, and accelerator technology that benefit numerous other scientific fields.

Natural Occurrence

SURVEYED
Roentgenium does not occur naturally anywhere in the universe under any currently known physical conditions and can only be created artificially through extraordinarily complex nuclear fusion reactions using the most advanced and powerful particle accelerator facilities available on Earth. The element is synthesized by bombarding extremely heavy target nuclei with lighter projectile nuclei accelerated to tremendous energies, typically using bismuth-209 targets and nickel-64 projectiles to create Roentgenium-272 through precisely controlled nuclear fusion processes. Production requires the most sophisticated heavy-ion accelerators in existence, capable of accelerating ions to exact energies while maintaining unprecedented accuracy in beam focusing, target positioning, timing synchronization, and detection systems. Even utilizing the most advanced accelerator technology available to modern science, only individual atoms of Roentgenium can be produced over extended periods, and these atoms decay through radioactive processes within seconds of their creation. The most stable known isotope, Roentgenium-282, has a half-life of approximately 100 seconds, while other isotopes decay significantly more rapidly, some within milliseconds of their formation in the accelerator target. The element's production is restricted to perhaps two or three specialized research facilities worldwide, including GSI in Germany and RIKEN in Japan, institutions possessing the extraordinary technological capabilities required for superheavy element synthesis. The completely synthetic nature of Roentgenium means it has absolutely no geological occurrence, no environmental presence whatsoever, and no natural formation processes anywhere in the known universe under current physical laws and conditions. All Roentgenium research must be conducted on individual atoms or extremely small numbers of atoms detected through their highly characteristic radioactive decay signatures, requiring the most sensitive and sophisticated detection equipment available to modern science. The total quantity of Roentgenium ever created by humanity would be far too minuscule to detect using any conventional measurement techniques, representing perhaps fewer than one hundred atoms produced over decades of intensive international research efforts. Environmental concentrations of Roentgenium are effectively zero everywhere in the universe, as the element cannot persist in nature due to its extremely rapid radioactive decay and the complete absence of any natural production mechanisms under normal stellar or planetary conditions. The element exists only momentarily in the highly controlled and specialized environment of nuclear physics laboratories before inevitably decaying into lighter elements within seconds to minutes of its artificial creation.

Discovery

ARCHIVED
1994
Roentgenium was first synthesized in 1994 by an international team of scientists led by Sigurd Hofmann at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany, using their state-of-the-art heavy-ion linear accelerator (UNILAC) and the most advanced detection systems available at the time. The historic discovery involved bombarding bismuth-209 targets with nickel-64 ions accelerated to extraordinarily high energies, successfully creating roentgenium-272 through nuclear fusion reactions and detecting its characteristic radioactive decay signature over approximately 1.5 minutes. The German research team employed the most sophisticated detection equipment available, including advanced position-sensitive detectors, time-of-flight measurement systems, and complex data analysis algorithms to identify roentgenium atoms through their unique decay chains and energy characteristics. The element was initially assigned the systematic placeholder name "unununium" (meaning "one-one-one" in Latin) according to International Union of Pure and Applied Chemistry (IUPAC) systematic naming conventions for newly discovered superheavy elements awaiting official recognition. The research team proposed the name "roentgenium" to honor German physicist Wilhelm Conrad Röntgen, who discovered X-rays in 1895 and became the first recipient of the Nobel Prize in Physics, recognizing his revolutionary contributions to physics and medical science. The discovery represented an extraordinary achievement in nuclear physics, requiring unprecedented precision in accelerator operation, target preparation, beam focusing, timing control, and detection methodology to create and positively identify atoms existing for mere minutes. The successful synthesis involved many years of intensive technological development in heavy-ion accelerator physics, ultra-sensitive particle detection systems, sophisticated data analysis techniques, and statistical methods for identifying extremely rare nuclear events against background noise. IUPAC officially approved the name "roentgenium" with the chemical symbol "Rg" in 2004 after comprehensive international review of the experimental evidence, independent verification attempts, and thorough confirmation of the discovery's scientific validity. The achievement demonstrated continuing rapid advancement in superheavy element research capabilities and provided essential experimental data for testing theoretical predictions about nuclear stability, atomic structure, and chemical properties at the extremes of the periodic table. This groundbreaking discovery opened exciting new possibilities for synthesizing even heavier elements and contributed fundamentally to understanding the absolute limits of nuclear structure, stability, and the theoretical island of stability. The extensive international collaboration required for this remarkable achievement exemplified the increasingly global nature of cutting-edge nuclear physics research and the critical importance of shared scientific knowledge, resources, and expertise.

Safety Information

CRITICAL
Roentgenium presents the most extreme radiological hazards encountered in nuclear physics research due to its intense radioactivity, relatively short half-life, and the extraordinarily high-energy nuclear processes required for its production, detection, and study. The primary safety concerns involve not the Roentgenium atoms themselves, which exist in negligible quantities for brief periods, but the incredibly intense and complex radiation fields generated during synthesis and the intricate cascade of highly radioactive decay products formed as the element undergoes successive radioactive transformations. Personnel working in Roentgenium research must utilize the most comprehensive and advanced radiation monitoring systems available to modern science and follow the most stringent safety protocols ever developed for nuclear physics research, specifically designed to minimize exposure to high-energy gamma radiation, neutron flux, alpha particles, and potential radioactive contamination. Research facilities must be equipped with multiple redundant layers of the most sophisticated radiation shielding systems possible, incorporating dense materials such as lead, tungsten, borated polyethylene, and specialized neutron-absorbing composites to protect workers from the intense multi-spectral radiation environment. The work environment requires continuous monitoring using multiple independent radiation detection systems with advanced automatic safety interlocks capable of instantaneously shutting down all operations if radiation levels exceed any predetermined safety threshold or if any safety system indicates potential
hazardous conditions.
All personnel must successfully complete extensive specialized training programs covering advanced radiation safety principles, emergency response procedures, nuclear physics hazards, superheavy element risks, and the specific safety protocols associated with Roentgenium research before being granted access to these highly restricted facilities. The half-life characteristics of Roentgenium mean it undergoes radioactive decay through multiple complex pathways, creating an intricate mixture of highly radioactive daughter products with varying decay modes, energies, and half-lives, each requiring specific containment, monitoring, and safety procedures. Comprehensive emergency response protocols must be continuously maintained and regularly practiced through realistic drills, covering scenarios including major radioactive contamination events, accelerator system malfunctions, detection equipment failures, medical emergencies involving radiation exposure, and facility evacuation procedures. All waste materials from Roentgenium research require specialized long-term storage in secure, continuously monitored facilities designed specifically for mixed radioactive waste containing various isotopes with different decay characteristics, radiation types, and long-term hazard potentials. Individuals who are pregnant, under 18 years of age, have compromised immune systems, or have certain medical conditions are absolutely prohibited from areas where Roentgenium research is conducted due to extreme sensitivity to radiation effects and potential for genetic damage or other serious health consequences. Research facilities must maintain the most detailed and comprehensive exposure monitoring records possible for all personnel and implement the strictest possible interpretation of ALARA (As Low As Reasonably Achievable) radiation protection principles through optimized procedures involving time minimization, distance maximization, and shielding optimization.

Knowledge Database

Essential information about Roentgenium (Rg)

Roentgenium is unique due to its atomic number of 111 and belongs to the Transition Metal category. With an atomic mass of 280.000000, it exhibits distinctive properties that make it valuable for various applications.

Roentgenium has several important physical properties:

State at Room Temperature: solid

Roentgenium has various important applications in modern technology and industry:

Roentgenium, being an extremely short-lived synthetic superheavy element with a half-life measured in seconds, has no practical applications outside of fundamental nuclear physics research and theoretical studies exploring the limits of atomic structure and nuclear stability. The element serves exclusively to advance scientific understanding of superheavy nuclei and provide crucial experimental data for testing theoretical predictions about the proposed island of stability where certain superheavy elements might have longer half-lives. Research with Roentgenium contributes to validating sophisticated nuclear shell models and understanding how protons and neutrons organize themselves in very heavy atomic nuclei at the extremes of nuclear physics. The element is used as an important testing ground for advanced theoretical models that attempt to predict the chemical and physical properties of superheavy elements through complex relativistic quantum mechanical calculations. Roentgenium research helps scientists understand how relativistic effects profoundly influence atomic behavior and chemical properties as elements become increasingly heavy and electrons approach significant fractions of light speed. The experimental techniques and instrumentation developed for creating and detecting Roentgenium have significantly advanced nuclear physics technology and contributed to major improvements in particle accelerator systems and ultra-sensitive detection equipment. Studies of Roentgenium provide invaluable data for understanding stellar nucleosynthesis processes and how the heaviest elements in the universe are formed during extreme astrophysical events such as neutron star collisions and supernovae. The element's research contributes substantially to training the next generation of nuclear physicists and developing cutting-edge experimental methodologies for studying rare nuclear phenomena at the absolute frontiers of current scientific capability. While Roentgenium itself has no practical applications, the fundamental research it enables significantly advances our understanding of nuclear processes that underlie many important technologies in nuclear medicine, nuclear power generation, and advanced materials science. The extensive international collaborative efforts required for Roentgenium research promote scientific cooperation and facilitate knowledge sharing among the global nuclear physics research community. Future discoveries of longer-lived Roentgenium isotopes or related superheavy elements might potentially reveal unique properties with applications in advanced scientific instrumentation or specialized technological fields.
1994
Roentgenium was first synthesized in 1994 by an international team of scientists led by Sigurd Hofmann at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany, using their state-of-the-art heavy-ion linear accelerator (UNILAC) and the most advanced detection systems available at the time. The historic discovery involved bombarding bismuth-209 targets with nickel-64 ions accelerated to extraordinarily high energies, successfully creating roentgenium-272 through nuclear fusion reactions and detecting its characteristic radioactive decay signature over approximately 1.5 minutes. The German research team employed the most sophisticated detection equipment available, including advanced position-sensitive detectors, time-of-flight measurement systems, and complex data analysis algorithms to identify roentgenium atoms through their unique decay chains and energy characteristics. The element was initially assigned the systematic placeholder name "unununium" (meaning "one-one-one" in Latin) according to International Union of Pure and Applied Chemistry (IUPAC) systematic naming conventions for newly discovered superheavy elements awaiting official recognition. The research team proposed the name "roentgenium" to honor German physicist Wilhelm Conrad Röntgen, who discovered X-rays in 1895 and became the first recipient of the Nobel Prize in Physics, recognizing his revolutionary contributions to physics and medical science. The discovery represented an extraordinary achievement in nuclear physics, requiring unprecedented precision in accelerator operation, target preparation, beam focusing, timing control, and detection methodology to create and positively identify atoms existing for mere minutes. The successful synthesis involved many years of intensive technological development in heavy-ion accelerator physics, ultra-sensitive particle detection systems, sophisticated data analysis techniques, and statistical methods for identifying extremely rare nuclear events against background noise. IUPAC officially approved the name "roentgenium" with the chemical symbol "Rg" in 2004 after comprehensive international review of the experimental evidence, independent verification attempts, and thorough confirmation of the discovery's scientific validity. The achievement demonstrated continuing rapid advancement in superheavy element research capabilities and provided essential experimental data for testing theoretical predictions about nuclear stability, atomic structure, and chemical properties at the extremes of the periodic table. This groundbreaking discovery opened exciting new possibilities for synthesizing even heavier elements and contributed fundamentally to understanding the absolute limits of nuclear structure, stability, and the theoretical island of stability. The extensive international collaboration required for this remarkable achievement exemplified the increasingly global nature of cutting-edge nuclear physics research and the critical importance of shared scientific knowledge, resources, and expertise.

Discovered by: Roentgenium was first synthesized in 1994 by an international team of scientists led by Sigurd Hofmann at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany, using their state-of-the-art heavy-ion linear accelerator (UNILAC) and the most advanced detection systems available at the time. The historic discovery involved bombarding bismuth-209 targets with nickel-64 ions accelerated to extraordinarily high energies, successfully creating roentgenium-272 through nuclear fusion reactions and detecting its characteristic radioactive decay signature over approximately 1.5 minutes. The German research team employed the most sophisticated detection equipment available, including advanced position-sensitive detectors, time-of-flight measurement systems, and complex data analysis algorithms to identify roentgenium atoms through their unique decay chains and energy characteristics. The element was initially assigned the systematic placeholder name "unununium" (meaning "one-one-one" in Latin) according to International Union of Pure and Applied Chemistry (IUPAC) systematic naming conventions for newly discovered superheavy elements awaiting official recognition. The research team proposed the name "roentgenium" to honor German physicist Wilhelm Conrad Röntgen, who discovered X-rays in 1895 and became the first recipient of the Nobel Prize in Physics, recognizing his revolutionary contributions to physics and medical science. The discovery represented an extraordinary achievement in nuclear physics, requiring unprecedented precision in accelerator operation, target preparation, beam focusing, timing control, and detection methodology to create and positively identify atoms existing for mere minutes. The successful synthesis involved many years of intensive technological development in heavy-ion accelerator physics, ultra-sensitive particle detection systems, sophisticated data analysis techniques, and statistical methods for identifying extremely rare nuclear events against background noise. IUPAC officially approved the name "roentgenium" with the chemical symbol "Rg" in 2004 after comprehensive international review of the experimental evidence, independent verification attempts, and thorough confirmation of the discovery's scientific validity. The achievement demonstrated continuing rapid advancement in superheavy element research capabilities and provided essential experimental data for testing theoretical predictions about nuclear stability, atomic structure, and chemical properties at the extremes of the periodic table. This groundbreaking discovery opened exciting new possibilities for synthesizing even heavier elements and contributed fundamentally to understanding the absolute limits of nuclear structure, stability, and the theoretical island of stability. The extensive international collaboration required for this remarkable achievement exemplified the increasingly global nature of cutting-edge nuclear physics research and the critical importance of shared scientific knowledge, resources, and expertise.

Year of Discovery: 1994

Roentgenium does not occur naturally anywhere in the universe under any currently known physical conditions and can only be created artificially through extraordinarily complex nuclear fusion reactions using the most advanced and powerful particle accelerator facilities available on Earth. The element is synthesized by bombarding extremely heavy target nuclei with lighter projectile nuclei accelerated to tremendous energies, typically using bismuth-209 targets and nickel-64 projectiles to create Roentgenium-272 through precisely controlled nuclear fusion processes. Production requires the most sophisticated heavy-ion accelerators in existence, capable of accelerating ions to exact energies while maintaining unprecedented accuracy in beam focusing, target positioning, timing synchronization, and detection systems. Even utilizing the most advanced accelerator technology available to modern science, only individual atoms of Roentgenium can be produced over extended periods, and these atoms decay through radioactive processes within seconds of their creation. The most stable known isotope, Roentgenium-282, has a half-life of approximately 100 seconds, while other isotopes decay significantly more rapidly, some within milliseconds of their formation in the accelerator target. The element's production is restricted to perhaps two or three specialized research facilities worldwide, including GSI in Germany and RIKEN in Japan, institutions possessing the extraordinary technological capabilities required for superheavy element synthesis. The completely synthetic nature of Roentgenium means it has absolutely no geological occurrence, no environmental presence whatsoever, and no natural formation processes anywhere in the known universe under current physical laws and conditions. All Roentgenium research must be conducted on individual atoms or extremely small numbers of atoms detected through their highly characteristic radioactive decay signatures, requiring the most sensitive and sophisticated detection equipment available to modern science. The total quantity of Roentgenium ever created by humanity would be far too minuscule to detect using any conventional measurement techniques, representing perhaps fewer than one hundred atoms produced over decades of intensive international research efforts. Environmental concentrations of Roentgenium are effectively zero everywhere in the universe, as the element cannot persist in nature due to its extremely rapid radioactive decay and the complete absence of any natural production mechanisms under normal stellar or planetary conditions. The element exists only momentarily in the highly controlled and specialized environment of nuclear physics laboratories before inevitably decaying into lighter elements within seconds to minutes of its artificial creation.

⚠️ Caution: Roentgenium is radioactive and requires special handling procedures. Only trained professionals should work with this element.

Roentgenium presents the most extreme radiological hazards encountered in nuclear physics research due to its intense radioactivity, relatively short half-life, and the extraordinarily high-energy nuclear processes required for its production, detection, and study. The primary safety concerns involve not the Roentgenium atoms themselves, which exist in negligible quantities for brief periods, but the incredibly intense and complex radiation fields generated during synthesis and the intricate cascade of highly radioactive decay products formed as the element undergoes successive radioactive transformations. Personnel working in Roentgenium research must utilize the most comprehensive and advanced radiation monitoring systems available to modern science and follow the most stringent safety protocols ever developed for nuclear physics research, specifically designed to minimize exposure to high-energy gamma radiation, neutron flux, alpha particles, and potential radioactive contamination. Research facilities must be equipped with multiple redundant layers of the most sophisticated radiation shielding systems possible, incorporating dense materials such as lead, tungsten, borated polyethylene, and specialized neutron-absorbing composites to protect workers from the intense multi-spectral radiation environment. The work environment requires continuous monitoring using multiple independent radiation detection systems with advanced automatic safety interlocks capable of instantaneously shutting down all operations if radiation levels exceed any predetermined safety threshold or if any safety system indicates potential
hazardous conditions.
All personnel must successfully complete extensive specialized training programs covering advanced radiation safety principles, emergency response procedures, nuclear physics hazards, superheavy element risks, and the specific safety protocols associated with Roentgenium research before being granted access to these highly restricted facilities. The half-life characteristics of Roentgenium mean it undergoes radioactive decay through multiple complex pathways, creating an intricate mixture of highly radioactive daughter products with varying decay modes, energies, and half-lives, each requiring specific containment, monitoring, and safety procedures. Comprehensive emergency response protocols must be continuously maintained and regularly practiced through realistic drills, covering scenarios including major radioactive contamination events, accelerator system malfunctions, detection equipment failures, medical emergencies involving radiation exposure, and facility evacuation procedures. All waste materials from Roentgenium research require specialized long-term storage in secure, continuously monitored facilities designed specifically for mixed radioactive waste containing various isotopes with different decay characteristics, radiation types, and long-term hazard potentials. Individuals who are pregnant, under 18 years of age, have compromised immune systems, or have certain medical conditions are absolutely prohibited from areas where Roentgenium research is conducted due to extreme sensitivity to radiation effects and potential for genetic damage or other serious health consequences. Research facilities must maintain the most detailed and comprehensive exposure monitoring records possible for all personnel and implement the strictest possible interpretation of ALARA (As Low As Reasonably Achievable) radiation protection principles through optimized procedures involving time minimization, distance maximization, and shielding optimization.

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Ag
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79
Au
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Fr
Francium
88
Ra
Radium
89
Ac
Actinium
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