Dubnium: the essentials
Dubnium is a synthetic element that is not present in the environment at all. It has no uses.
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: physical properties
Dubnium: orbital properties
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.