Bohrium

Bohrium, ₁₀₇Bh
Bohrium
Pronunciation	/ˈbɔːriəm/ ⓘ (BOR-ee-əm)
Mass number	[270] (unconfirmed: 278)
Bohrium in the periodic table
	seaborgium ← bohrium → hassium
Atomic number (Z)	107
Group	group 7
Period	period 7
Block	d-block
Electron configuration	[Rn] 5f14 6d5 7s2
Electrons per shell	2, 8, 18, 32, 32, 13, 2
Physical properties
Phase at STP	solid (predicted)
Density (near r.t.)	26–27 g/cm3 (predicted)
Atomic properties
Oxidation states	(+3), (+4), (+5), +7 (parenthesized: prediction)
Ionization energies	1st: 740 kJ/mol ; 2nd: 1690 kJ/mol ; 3rd: 2570 kJ/mol ; (more) (all but first estimated);
Atomic radius	empirical: 128 pm (predicted)
Covalent radius	141 pm (estimated)
Other properties
Natural occurrence	synthetic
Crystal structure	hexagonal close-packed (hcp) ; (predicted)
CAS Number	54037-14-8
History
Naming	after Niels Bohr
Discovery	Gesellschaft für Schwerionenforschung (1981)
Isotopes of bohrium

Bohrium is a synthetic chemical element; it has symbol Bh and atomic number 107. It is named after Danish physicist Niels Bohr. As a synthetic element, it can be created in particle accelerators but is not found in nature. All known isotopes of bohrium are highly radioactive; the most stable known isotope is ²⁷⁰Bh with a half-life of approximately 2.4 minutes, though the unconfirmed ²⁷⁸Bh may have a longer half-life of about 11.5 minutes.

In the periodic table, it is a d-block transactinide element. It is a member of the 7th period and belongs to the group 7 elements as the fifth member of the 6d series of transition metals. Chemistry experiments have confirmed that bohrium behaves as the heavier homologue to rhenium in group 7. The chemical properties of bohrium are characterized only partly, but they compare well with the chemistry of the other group 7 elements.

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