HASSIUM

Introduction

Atomic Number: 108
Group: 8 or VIII B
Atomic Weight: 277
Period: 7
CAS Number: 54037-57-9

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 was first synthesized and identified in 1984 by the same G.S.I. Darmstadt group who first identified Elements 107 and 109. Presumably this element will have chemical properties similar to osmium. Isotope 265108 was produced using a beam of 58Fe projectiles, produced by the Universal Linear Accelerator (UNILAC) to bombard a 208Pb target. Discovery of Elements 107 and 109 was made using detection of isotopes with odd proton and neutron numbers. Elements having even atomic numbers are thought to be less stable against spontaneous fusion than odd elements. The production of 265108 in the same reaction as was used at G.S.I. was confirmed at Dubna with detection of the 7th member of the decay chain 253Es. Isotopes of Element 108 were believed to decay by spontaneous fission, explaining why 109 was produced before 108. Isotope 265108 and 266108 are thought to decay to 261106, which in turn decays to 257104 and 253No. The IUPAC adopted the name hassium, after the German state of Hesse, in 1997. 1

Physical Properties

Density:   g/cm3

* - at 1 atm

Electron Configuration

Electron Configuration: [Rn] 7s2 5f14 6d6
Block: d
Highest Occupied Energy Level: 7
Valence Electrons: 

Quantum Numbers:

n = 6
ℓ = 2
m = -2
ms = -½

Bonding

Isotopes

Nuclide Mass 2 Half-Life 2 Nuclear Spin 2 Binding Energy
263Hs 263.12856(37)# 1# ms 7/2+# 1,926.48 MeV
264Hs 264.12839(5) 540(300) μs 0+ 1,934.55 MeV
265Hs 265.13009(15)# 2.1(3) ms [2.0(+3-2) ms] 9/2+# 1,933.31 MeV
266Hs 266.13010(31)# 2.7(10) ms [2.3(+13-6) ms] 0+ 1,941.38 MeV
267Hs 267.13179(11)# 32(15) ms 3/2+# 1,949.45 MeV
268Hs 268.13216(44)# 2# s 0+ 1,957.52 MeV
269Hs 269.13406(13)# 27(17) s 1,965.59 MeV
270Hs 270.13465(31)# 3.6(+8-14) s 0+ 1,973.66 MeV
271Hs 271.13766(36)# 40# s 1,981.74 MeV
272Hs 272.13905(62)# 40# s 0+ 1,989.81 MeV
273Hs 273.14199(89)# 50# s (3/2+)# 1,988.56 MeV
274Hs 274.14313(70)# 1# min 0+ 1,996.64 MeV
275Hs 275.14595(77)# 0.15(+27-6) s 2,004.71 MeV
276Hs 276.14721(89)# 1# h 0+ 2,012.78 MeV
277Hs 277.14984(78)# 40(30) min 3/2+# 2,020.85 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. 2

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 4:14.
(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) - Atomic Mass Data Center. http://amdc.in2p3.fr/web/nubase_en.html (accessed July 14, 2009).