Bohrium

Bohrium (chemical symbol: Bh) is a synthetic element with atomic number 107. It is an extremely heavy element that does not occur naturally on Earth; it is produced in equipment called an accelerator, a machine that collides atoms at high velocities. All known isotopes of it are radioactive and decay rapidly.

The name was given in honour of Danish physicist Niels Bohr, who made significant contributions to the theory of atomic structure. This name was officially recognised by the International Union of Pure and Applied Chemistry (IUPAC) in the 1990s.

Position in the periodic table

Bohrium is located in group 7 of the periodic table, in the same period as manganese, technetium, and rhenium. Its chemistry is therefore expected to resemble that of rhenium: for example, it may form oxide compounds with an oxidation state of +7. It is one of the transactinide elements, which are the elements beyond the actinides on the table.

Production and history

In 1981, a German research team working at the GSI facility in Darmstadt reported that they had created bohrium atoms by bombarding chromium with bismuth. Before this, a Soviet team working at Dubna reported similar results, leading to a prolonged dispute over naming and recognition. IUPAC ultimately decided on the name Bohrium.

Properties and research

Because only small quantities of atoms can be produced at any one time—sometimes just a few atoms—physical properties such as density and melting point cannot be measured directly; they are estimated through calculation and comparison with elements in the same group. Chemical research on bohrium relies on rapid experiments to observe how it behaves as a gas or in solution before it decays.

Applications

Bohrium has no commercial use. It is used only in pure research, particularly in studies of the boundaries of the heavy nucleus and in testing predictions of the periodic table.