Dubnium: the essentials
- Name: dubnium
- Symbol: Db
- Atomic number: 105
- Relative atomic mass (Ar): [ 270 ] (longest lived isotope)
- Standard state: presumably a solid at 298 K
- Appearance: 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
- Shell structure: 184.108.40.206.32.11.2
- CAS Registry: 53850-35-4
Dubnium atoms have 105 electrons and the shell structure is 220.127.116.11.32.11.2. 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).
Dubnium is a synthetic element that is not present in the environment at all. It has no uses.
Dubnium: physical properties
- Density of solid: 21600 (predicted) kg m-3
- Molar volume: 12 (rough estimate based upon density estimate) cm3
- Thermal conductivity: 58 (estimate) W m‑1 K‑1
Dubnium: heat properties
- Melting point: (no data) K
- Boiling point: (no data) K
- Enthalpy of fusion: 20.5 kJ mol-1
Dubnium: atom sizes
- Atomic radius (empirical): (no data) pm
- Molecular single bond covalent radius: 149 (coordination number 5) ppm
- van der Waals radius: (no data) ppm
- Pauling electronegativity: (no data) (Pauling units)
- Allred Rochow electronegativity: (no data) (Pauling units)
- Mulliken-Jaffe electronegativity: (no data)
Dubnium: orbital properties
- First ionisation energy: 656 (calculated) kJ mol‑1
- Second ionisation energy: 1350 kJ mol‑1
- Third ionisation energy: 2230 kJ mol‑1
- Universe: (no data) ppb by weight
- Crustal rocks: (no data) ppb by weight
- Human: (no data) ppb by weight
Dubnium: crystal structure
Dubnium: biological data
- Human abundance by weight: (no data) ppb by weight
Dubnium has no biological role.
Reactions of dubnium as the element with air, water, halogens, acids, and bases where known.
Dubnium: binary compounds
Binary compounds with halogens (known as halides), oxygen (known as oxides), hydrogen (known as hydrides), and other compounds of dubnium where known.
Dubnium: compound properties
Bond strengths; lattice energies of dubnium halides, hydrides, oxides (where known); and reduction potentials where known.
Dubnium: historyDubnium was discovered by Workers at the Nuclear Institute at Dubna, and the University of California, Berkeley, USA. in 1967 at USSR, United States. Origin of name: the origin of the name dubnium is the Joint Nuclear Institute at Dubna", an institute heavily involved in the search for heavy elements.
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.