Bohrium

It is a synthetic element whose most stable known isotope 270Bh, has a half-life of 61 seconds. Chemical experiments have confirmed bohrium's predicted position as a heavier homologue to rhenium with the formation of a stable +7 oxidation state.
 * Bohrium** is a chemical element with the symbol **Bh** and atomic number 107 and is the heaviest member of group 7 (VIIB).
 * Name:** Bohrium
 * Symbol:** Bh
 * Atomic Number:** 107
 * Atomic Mass:** (262.0) amu
 * Melting Point:** Unknown
 * Boiling Point:** Unknown
 * Number of Protons/Electrons:** 107
 * Number of Neutrons:** 155
 * Classification:** Transition Metal
 * Crystal Structure:** Unknown
 * Density @ __293__ K:** Unknown
 * Color:** Unknown
 * Other Names:** Unnilseptium (Uns), Bohrium (Bh), Nielsbohrium (Ns)

Atomic Structure

 * ||  || **Number of Energy Levels:** 7
 * First Energy Level:** 2
 * Second Energy Level:**8
 * Third Energy Level:** 18
 * Fourth Energy Level:**32
 * Fifth Energy Level:** 32
 * Sixth Energy Level:**13
 * Seventh Energy Level:**2 ||

Isotopes

 * ** Isotope ** || ** Half Life ** ||
 * Bh-261 || 0.01 seconds ||
 * Bh-262 || 0.1 seconds ||
 * Bh-262m || 0.0080 seconds ||

Facts

 * Date of __Discovery__:** 1976
 * Discoverer:** Peter Armbruster, Gottfried Munzenber and others
 * Name Origin:** After Niels Bohr (Danish physicist)
 * Uses:** No uses known
 * Obtained From:** Man-made

First produced in 1976 by scientists working at the Joint Institute for Nuclear Research in Dubna, Russia, and later confirmed in 1981 by Peter Armbruster, Gottfried Münzenber and their team working at the Gesellschaft für Schwerionenforschung in Darmstadt, Germany, bohrium was produced by bombarding a target of bismuth-209 with ions of chromium-54. Bohrium's most stable isotope, bohrium-274, has a half-life of about 1.3 minutes. It decays into dubnium-270 through alpha decay. Since only a few atoms of bohrium have ever been made, there are currently no uses for bohrium outside of basic scientific research.
 * What's in a name?** Named after the scientist Niels Bohr.
 * Say what?** Bohrium is pronounced as **BORE-ee-em**.
 * History and Uses:**
 * Estimated Crustal Abundance:** Not Applicable
 * Estimated Oceanic Abundance:** Not Applicable
 * Number of Stable Isotopes:** 0
 * Ionization Energy:** Unknown
 * Oxidation State:** Unknown

Experimental
In 1995, the first report on attempted isolation of the element was unsuccessful.[|[][|23][|]] In 2000, it was confirmed that although relativistic effects are important, the 107th element does behave like a typical [|group 7 element].[|[][|24][|]] In 2000, a team at the PSI conducted a __chemistry__ reaction using atoms of 267Bh produced in the reaction between Bk-249 and Ne-22 ions. The resulting atoms were thermalised and reacted with a HCl/O2 mixture to form a volatile oxychloride. The reaction also produced isotopes of its lighter homologues, [|technetium] (as 108Tc) and [|rhenium] (as 169Re). The isothermal adsorption curves were measured and gave strong evidence for the formation of a volatile oxychloride with properties similar to that of rhenium oxychloride. This placed bohrium as a typical member of group 7.[|[][|3][|]]

Official discovery
The first convincing synthesis was in 1981 by a German research team led by [|Peter Armbruster] and [|Gottfried Münzenberg] at the [|Gesellschaft für Schwerionenforschung] (Institute for Heavy Ion Research, GSI) in [|Darmstadt] using the Dubna reaction. 209 83  Bi + 54 24  Cr → 262 107  Bh + n   In 1989, the GSI team successfully repeated the reaction during their efforts to measure an [|excitation function]. During these experiments, 261Bh was also identified in the 2n evaporation channel and it was confirmed that 262Bh exists as two states - a ground state and an [|isomeric] state. The IUPAC/IUPAP Transfermium Working Group report in 1992 officially recognised the GSI team as discoverers of bohrium.



Extrapolated
Bohrium is projected to be the fourth member of the 6d series of transition metals and the heaviest member of group VII in the Periodic Table, below [|manganese],[|technetium] and [|rhenium]. All the members of the group readily portray their group oxidation state of +7 and the state becomes more stable as the group is descended. Thus bohrium is expected to form a stable +7 state. Technetium also shows a stable +4 state whilst rhenium exhibits stable +4 and +3 states. Bohrium may therefore show these lower states as well.

The heavier members of the group are known to form volatile heptoxides M2O7, so bohrium should also form the volatile oxide Bh2O7. The oxide should dissolve in water to form perbohric acid, HBhO4. Rhenium and technetium form a range of oxyhalides from the halogenation of the oxide. The chlorination of the oxide forms the oxychlorides MO3Cl, so BhO3Cl should be formed in this reaction. Fluorination results in MO3F and MO2F3 for the heavier elements in addition to the rhenium compounds ReOF5 and ReF7. Therefore, oxyfluoride formation for bohrium may help to indicate eka-rhenium properties.

Experimental
In 1995, the first report on attempted isolation of the element was unsuccessful.[|[23]]

In 2000, it was confirmed that although relativistic effects are important, the 107th element does behave like a typical [|group 7 element].[|[24]]

In 2000, a team at the PSI conducted a chemistry reaction using atoms of 267Bh produced in the reaction between Bk-249 and Ne-22 ions. The resulting atoms were thermalised and reacted with a HCl/O2 mixture to form a volatile oxychloride. The reaction also produced isotopes of its lighter homologues, [|technetium] (as108Tc) and [|rhenium] (as 169Re). The isothermal adsorption curves were measured and gave strong evidence for the formation of a volatile oxychloride with properties similar to that of rhenium oxychloride. This placed bohrium as a typical member of group 7.

The only confirmed example of isomerism in bohrium is for the isotope 262Bh. Direct production populates two states, a ground state and an isomeric state. The ground state is confirmed as decaying by alpha emission with alpha lines at 10.08,9.82 and 9.76 MeV with a revised half-life of 84 ms. The excited state decays by alpha emission with lines at 10.37 and 10.24 MeV with a revised half-life of 9.6 ms.