dubnium

noun Chemistry, Physics.

1. a superheavy, synthetic, radioactive element with a very short half-life. Symbol: Db; atomic number: 105.

noun

1. a synthetic transactinide element produced in minute quantities by bombarding plutonium with high-energy neon ions. Symbol: Du; atomic no 105See hahnium

Db

1. 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.