BOHRIUM

Introduction

Atomic Number: 107
Group: 7 or VII B
Atomic Weight: 264
Period: 7
CAS Number: 54037-14-8

Classification

Chalcogen
Halogen
Noble Gas
Lanthanoid
Actinoid
Rare Earth Element
Platinum Group Metal
Transuranium
No Stable Isotopes
Solid
Liquid
Gas
Solid (Predicted)

Description • Uses/Function

This element, expected to have chemical properties similar to rhenium, was synthesized and unambiguously identified in 1981, using the Universal Linear Accelerator (UNILAC) at the Gesellschaft für Schwerionenforschung (G.S.I.) in Darmstadt, Germany. The discovery team was led by Armbruster and Münzenberg. The reaction producing the element was proposed and applied earlier by a Dubna Group led by Oganessian in 1976. A target of 209Bi was bombarded by a beam of 54Cr ions. In 1983 experiments at Dubna using the 157 -inch cyclotron, produced 262Bh by the reaction 209Bi + 54Cr. The alpha decay of 246Cf, the sixth member in the decay chain of 262Bh, served to establish a 1-neutron reaction channel. 1

Physical Properties

Density:   g/cm3

* - at 1 atm

Electron Configuration

Electron Configuration: [Rn] 7s2 5f14 6d5
Block: d
Highest Occupied Energy Level: 7
Valence Electrons: 

Quantum Numbers:

n = 6
ℓ = 2
m = 2
ms = +½

Bonding

Thermochemistry

Specific Heat: 
Thermal Conductivity:  (W/m)/K, 27°C 2
Heat of Fusion: 
Heat of Vaporization: 
State of Matter Enthalpy of Formation (ΔHf°)3 Entropy (S°)3 Gibbs Free Energy (ΔGf°)3
(kcal/mol) (kJ/mol) (cal/K) (J/K) (kcal/mol) (kJ/mol)
(g) 107.46 449.61264 41.05 171.7532 100.29 419.61336

Isotopes

Nuclide Mass 4 Half-Life 4 Nuclear Spin 4 Binding Energy
260Bh 260.12197(62)# 0.3# ms 1,903.05 MeV
261Bh 261.12166(25)# 13(4) ms [12(+5-3) ms] 1,911.12 MeV
262Bh 262.12289(37)# 290(160) ms 1,919.19 MeV
263Bh 263.12304(39)# 200# ms 1,927.26 MeV
264Bh 264.1246(3)# 1.3(5) s [0.44(+60-16) s] 1,935.33 MeV
265Bh 265.12515(41)# 0.9(+7-3) s 1,943.41 MeV
266Bh 266.12694(22)# 5(3) s 1,951.48 MeV
267Bh 267.12765(28)# 22(10) s [17(+14-6) s] 1,959.55 MeV
268Bh 268.12976(41)# 25# s 1,967.62 MeV
269Bh 269.13069(44)# 25# s 1,966.38 MeV
270Bh 270.13362(50)# 30# s 1,974.45 MeV
271Bh 271.13518(60)# 40# s 1,982.52 MeV
272Bh 272.13803(65)# 10(+12-4) s 1,990.59 MeV
273Bh 273.13962(89)# 90# min 1,998.66 MeV
274Bh 274.14244(84)# 90# min 1,997.42 MeV
275Bh 275.14425(70)# 40# min 2,005.49 MeV
Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses. 4

Abundance

Safety Information


Material Safety Data Sheet - ACI Alloys, Inc.

For More Information

External Links:

Sources

(1) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:6.
(2) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:123-6:137.
(3) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:107-6:122.
(4) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:4-9:94.
(5) - Atomic Mass Data Center. http://amdc.in2p3.fr/web/nubase_en.html (accessed July 14, 2009).