Dubnium (Db)
Dubnium (Db) is element 105 of the periodic table, a transition metal in period 7 and group 5. It has no stable isotope and no standard atomic weight; 268 is the mass number of its longest-lived isotope. At room temperature it is a solid.
| Atomic number | 105 |
|---|---|
| Symbol | Db |
| Standard atomic weight | [268] (mass number of the longest-lived isotope) |
| Molar mass | [268] g/mol |
| Category | Transition metal |
| Group | 5 |
| Period | 7 |
| Block | d-block |
| Electron configuration | [Rn] 7s2 5f14 6d3 |
| Oxidation states | +5, +4, +3 |
| Electronegativity (Pauling) | — |
| Atomic radius (van der Waals) | — |
| First ionisation energy | — |
| Electron affinity | — |
| State at room temperature | Solid |
| Melting point | — |
| Boiling point | — |
| Density | — |
| Discovered | 1967 |
Group 5
Calculate with Dubnium
Atomic weight: IUPAC CIAAW — no standard atomic weight; mass number in brackets. Other properties: PubChem (U.S. National Library of Medicine, public domain). Values such as melting point and radius depend on how they were measured; check a data book for precise work.