Structure
Not a diagram of dots on rings — a Monte-Carlo sample of the actual probability density |ψ|² for each occupied subshell. Drag to rotate. Blue and violet mark opposite signs of the wavefunction, which is what makes bonding possible.
Measured values
Every bar shows where dubnium sits among all 118 elements for that property.
Sources: IUPAC 2021 standard atomic weights · CRC Handbook of Chemistry and Physics · NIST. Values marked ~ are predicted rather than measured.
Size, to scale
Radius 247 pm — that is 0.247 nm, so about 2024 million of them side by side would span a millimetre.
Thermal range
Neither transition has been measured for dubnium — too few atoms have ever existed at once.
The story
Named after Dubna, the Russian town where much of superheavy chemistry was pioneered.
Dubnium's discovery became another intense Cold War rivalry between Soviet scientists at Dubna and American researchers at Berkeley. Both teams claimed priority in creating element 105, leading to competing names and a decades-long controversy resolved by international committee.
In 1967, Georgy Flerov's team at the Joint Institute for Nuclear Research reported creating element 105 by bombarding americium-243 with neon-22 ions. They proposed naming it "nielsbohrium" after Danish physicist Niels Bohr, pioneer of atomic structure theory.
In 1970, Albert Ghiorso's team at Berkeley Lab reported independent synthesis using berkelium-249 bombarded with nitrogen-15 ions. They proposed "hahnium" honoring German chemist Otto Hahn, discoverer of nuclear fission, creating a diplomatic naming dilemma.
IUPAC resolved the controversy by adopting "dubnium" in 1997, honoring the Russian research city Dubna where the Joint Institute for Nuclear Research is located. This decision recognized both teams' contributions while selecting a geographically neutral name.
Recent advanced detection techniques have confirmed dubnium's properties and enabled discovery of new isotopes, including the 2025 identification of dubnium-255 with detailed fission studies, validating theoretical predictions about superheavy nuclear behavior.
Applications
Dubnium serves as a crucial test subject for understanding chemical periodicity in superheavy elements, helping scientists determine how chemical properties change under extreme nuclear charge conditions. Research focuses on validating theoretical predictions about Group 5 chemistry in the superheavy region.
Scientists use dubnium to investigate spontaneous fission processes and nuclear stability limits. The recent discovery of dubnium-255 provides new insights into odd-Z isotope fission behavior, contributing to understanding of nuclear structure at the limits of atomic existence.
Dubnium enables groundbreaking studies of relativistic chemistry where electron speeds approach significant fractions of light velocity due to extreme nuclear charge. These studies validate quantum mechanical calculations and predict chemical behavior of even heavier undiscovered elements.
Research teams employ dubnium data to test and refine theoretical nuclear models that predict superheavy element properties, stability, and optimal synthesis pathways. This research guides future attempts to create elements in the predicted "island of stability."
Dubnium studies drive innovation in superheavy element production methods, including optimization of ion beam energies, target preparation techniques, and separation chemistry for isolating individual atoms from complex reaction products.
Dubnium applications remain confined to elite nuclear research laboratories including GSI Helmholtz Centre, Berkeley Lab, RIKEN, and the Flerov Laboratory at JINR Dubna. These institutions use dubnium for fundamental superheavy element physics and chemistry research.
Research teams utilize dubnium in precision nuclear measurements including alpha-decay spectroscopy, gamma-ray detection, and nuclear lifetime determination. These experiments provide essential data for understanding nuclear structure in the superheavy element region.
Scientists perform pioneering atom-at-a-time chemistry with dubnium, investigating chemical properties using advanced chromatography and extraction techniques. These studies represent a leading frontier where individual atoms can be chemically characterized.
Dubnium research necessitates development of ultra-sensitive detection systems including magnetic separators, time-of-flight analyzers, and sophisticated particle identification systems that push the boundaries of nuclear instrumentation capabilities.
Where it comes from
0 mg/kg of Earth's crust · more abundant than 0% of elements
Dubnium does not exist naturally anywhere in the universe and can only be created through artificial nuclear synthesis in advanced particle accelerators. This superheavy element represents matter that has never existed naturally since cosmic nucleosynthesis began.
Scientists create dubnium by bombarding berkelium-249 targets with nitrogen-15 ions, or by bombarding americium-243 with neon-22 ions in linear accelerators. These fusion reactions require precise energy calibration to overcome enormous electrostatic barriers.
The most stable dubnium isotope, 268Db, has a half-life of only 1.2 days, while most isotopes decay within seconds or minutes. The recently discovered 255Db demonstrates the range of nuclear stability in odd-Z superheavy isotopes.
Worldwide dubnium production is measured in single atoms per synthesis event, with successful experiments producing perhaps 1-5 atoms per hour during optimal runs. Global annual production totals fewer than thousands of atoms across all facilities.
Unlike elements formed through stellar nucleosynthesis, supernovae, or cosmic ray interactions, dubnium cannot form naturally due to its extremely short half-life and highly specific nuclear reaction requirements. It exists only through human technological achievement.
Handling
Dubnium is radioactive. It has no stable isotope — every nucleus decays. Handling requires appropriate shielding and licensing.
EXTREME CAUTION: Dubnium is a highly radioactive superheavy element that undergoes alpha decay and spontaneous fission, emitting dangerous high-energy particles and neutron radiation. Even microscopic quantities require maximum radiation protection and specialized containment systems.
Dubnium isotopes emit high-energy alpha particles and undergo spontaneous fission, creating multiple radiation hazards including fission fragments, neutrons, and gamma rays. Internal contamination would cause severe radiation poisoning and potentially fatal acute radiation syndrome.
Research requires heavily shielded hot cells, remote handling systems, neutron detection equipment, and continuous multi-parameter radiation monitoring. Personnel must maintain safe distances and use robotic manipulation exclusively when working with dubnium samples.
All materials contacting dubnium become high-level radioactive waste requiring specialized long-term storage and monitoring. Contamination creates persistent radiation hazards that must be managed according to the strictest nuclear safety protocols and regulations.
Quick answers
Dubnium (symbol Db) is element 105 on the periodic table, a transition metal in period 7, group 5. Named after Dubna, the Russian town where much of superheavy chemistry was pioneered. At room temperature it is a solid, and it is radioactive.
[Rn] 5f¹⁴ 6d³ 7s², giving 7 occupied shells holding 2, 8, 18, 32, 32, 11, 2 electrons respectively.Dubnium has no stable isotope, so it has no standard atomic weight. The figure quoted, 268, is the mass number of its longest-lived known isotope.
Dubnium has a density of 29.3 g/cm³. Water is 1.0 g/cm³, so a block of dubnium is about 29.3× heavier.
Dubnium was discovered in 1967 by JINR Dubna & Berkeley. It is named after dubna, Russia.
Dubnium does not occur naturally on Earth in any meaningful quantity — it is made in a reactor or an accelerator.
Yes. Dubnium has no stable isotope — every one of its nuclei decays. It does not occur in usable quantities in nature and must be synthesised.