Dubnium does not occur naturally in the Earth’s crust. Credit for the first synthesis of this
element
is given jointly to Albert Ghiorso and his team at the University of California in
Berkeley and Georgi Flerov and his team at the Joint Institute for Nuclear Research (JINR) in
Dubna, Russia (Figure 1). The element is named for the location of the Joint Institute for Nuclear
Research (JINR) laboratory in Dubna, Russia [656, 657]. Dubnium has no isotopic applications
outside of scientific research.
Stable
isotope
Relative
atomic mass
Mole
fraction
(none)
Fig. 1: The
cyclotron
U-300 is a 300-cm heavy-ion cyclotron built at the international Joint
Institute for Nuclear Research (JINR) and put into operation in 1960. (Photo used with
permission from Ivo J. Zvara, Joint Institute for Nuclear Research (JINR)). (Photo Source: Ivo J.
Zvara, American Chemical Society, 2003) [656].
Glossary
atomic number (Z) – The number of protons in the nucleus of an atom.
cyclotron – an apparatus in which charged atomic and subatomic particles are accelerated by a
rapidly varying (radio frequency) electric field while following an outward spiral path in a
constant magnetic field.
[return]
electron – elementary particle of matter with a negative electric charge
and a rest mass of about
9.109 × 10
–31
kg.
element (
chemical element) – a species of atoms; all atoms with the same number of
protons in
the atomic nucleus. A pure chemical substance composed of atoms with the same number of
protons in the atomic nucleus [703].
[return]
neutron – an elementary particle with no net charge and a rest mass of about 1.675 × 10
–27
kg,
slightly more than that of the
proton. All atoms contain neutrons in their nucleus except for
protium (
1
H).
proton – an elementary particle having a rest mass of about 1.673 × 10
–27
kg, slightly less than
that of a neutron, and a positive electric charge equal and opposite to that of the electron. The
number of protons in the nucleus of an atom is the atomic number.
References
656.
I. J. Zvara.
Chemical & Engineering News Archive.
81 (36) (2003). 10.1021/cen-
v081n036.p182
657.
L. A. N. Laboratory. Periodic Table of Elements: LANL- Dubnium. Los Alamos National
Laboratory. 2014 Feb. 25.
http://periodic.lanl.gov/105.shtml
703.
I. U. o. P. a. A. Chemistry.
Compendium of Chemical Terminology, 2nd ed. (the "Gold
Book"). Blackwell Scientific Publications, Oxford (1997).