noun Chemistry, Physics.
- a former name of dubnium. Symbol: Unp
noun Chemistry, Physics.
- a proposed name for dubnium. Symbol: Ha
noun Chemistry, Physics.
- a superheavy, synthetic, radioactive element with a very short half-life. Symbol: Db; atomic number: 105.
noun Chemistry, Physics.
- dubnium.
noun
- a synthetic transactinide element produced in minute quantities by bombarding plutonium with high-energy neon ions. Symbol: Du; atomic no 105See hahnium
noun
- a name once advanced by the American Chemical Society for a transuranic element, artificially produced from californium, atomic no: 105; half-life of most stable isotope, 262 Ha: 40 secondsNow called dubnium
Db
- A synthetic, radioactive element that is produced from californium, americium, or berkelium. Its most long-lived isotopes have mass numbers of 258, 261, 262, and 263 with half-lives of 4.2, 1.8. 34, and 30 seconds, respectively. Atomic number 105. See Periodic Table.