Dubnium: the essentials
Dubnium is a synthetic element that is not present in the environment at all. It has no uses.
- Name: dubnium
- Symbol: Db
- Atomic number: 105
- Relative atomic mass (Ar): [ 268 ]
- Standard state: presumably a solid at 298 K
- Colour: unknown, but probably metallic and silvery white or grey in appearance
- Classification: Metallic
- Group in periodic table: 5
- Group name: (none)
- Period in periodic table: 7
- Block in periodic table: d-block
- Electron shell structure: 2.8.18.32.32.11.2
- CAS Registry ID: 53850-35-4
Dubnium: historical information
Dubnium apparently was synthesized by Russian and American workers independently by bombardment technologies. Its actual isolation as the free element has not been accomplished. In 1967, Flerov reported element 105 after experiments at the Joint Research Institute in Russia involving reactions between 243Am ions with 22Ne ions. In 1970, Ghiorso and others announced their synthesis of dubnium at Berkeley (California) in the USA. This method involved the collsion of 249Cf ions with 15N ions.
Dubnium around us Read more »
Dubnium has no biological role.
Dubnium is a synthetic element that is not present in the geosphere.
| Location | ppb by weight | ppb by atoms | Links |
|---|---|---|---|
| Universe | (no data) | (no data) | 
|
| Crustal rocks | (no data) | (no data) | 
|
| Human | (no data) ppb by weight | (no data) atoms relative to C = 1000000 | 
|
Physical properties Read more »
Density of solid: 21600 (predicted) kg m-3
Molar volume: |196| cm3
Thermal conductivity: |206| W m‑1 K‑1
Heat properties Read more »
Melting point: (no data) K
Boiling point: (no data) K
Enthalpy of fusion: |203| kJ mol-1
Crystal structure Read more »
The solid state structure of dubnium is: .
Dubnium: orbital properties Read more »
Dubnium atoms have 105 electrons and the shell structure is 2.8.18.32.32.11.2. The ground state electronic configuration of neutral Dubnium is [Rn].5f14.6d3.7s2 (a guess based upon that of tantalum) and the term symbol of Dubnium is 4F3/2 (a guess based upon guessed electronic structure).
Pauling electronegativity: (no data) (Pauling units)
First ionisation energy: (no data) kJ mol‑1
Second ionisation energy: (no data) kJ mol‑1
Isolation
Isolation: only very small amounts of of element 105, dubnium, have ever been made. The first samples were made through nuclear reactions involving fusion of an isotope of californium, 249Cf, with one of nitrogen, 14N. A second route to the same isotope via berkelium is also known
15N + 249Cf → 261105Db + 4 1n
16N + 249Bk → 261105Db + 4 1n
Isolation of an observable quantity of dubnium has never been achieved.
Dubnium isotopes Read more »
| Isotope | Mass /Da |
Natural abund. (atom %) |
Nuclear spin (I) |
Nuclear magnetic moment (μ/μN) |
|---|---|---|---|---|
| nil |
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