Hassium

Hassium was first synthesized in 1984 by a German research team led by Peter Armbruster and Gottfried Munzenberg at the Institute for Heavy Ion Research (Gesellschaft für Schwerionenforschung) in Darmstadt. Some controversy appears to exist regarding the process of identifying Element 108.

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 1984 experiments at Dubna using the 157-inch cyclotron, produced ²⁶²107 by the reaction ²⁰⁹Bi + ⁵⁴Cr. The alpha decay of ²⁴⁶Cf, the sixth member in the decay chain of ²⁶²107, served to establish a 1-neutron reaction channel.

They bombarded atoms of ¹⁰⁸Pb with ions of ⁵⁸Fe with a device known as a linear accelerator. This produced atoms of hassium-265, an isotope with a half-life of about 2 milliseconds (0.002 seconds), and a free neutron.

The name hassium was proposed by Peter Armbruster and Gottfried Munzenberg, derived from the Latin name for the German state of Hessen where the institute is located.

There was an element naming controversy as to what the elements from 101 to 109 were to be called; thus IUPAC adopted unniloctium symbol Uno) as a temporary element name for this element. In 1994 a committee of IUPAC recommended that element 108 be named hahnium. The name hassium was adopted internationally in 1997.

Hassium's most stable isotope, hassium-277, has a half-life of about 40 minutes. It decays into seaborgium-273 through alpha decay or decays through spontaneous fission.

Isotope-270 of Hassium, discovered by an international team of scientists led by the Technical University of Munich in December 2006, is a doubly magic isotope with an unusually long half-life of 22 seconds. The existence of such relatively stable heavy isotopes had already been theoretically predicted, with some theories suggesting Hassium-270 may form part of an island of stability.

Isotope	Atomic Mass	Half-Life
²⁶³Hs	263.12856	~1 ms
²⁶⁴Hs	264.12839	540 µs
²⁶⁵Hs	265.13009	2.1 ms
²⁶⁶Hs	266.13010	2.7 ms
²⁶⁷Hs	267.13179	32 ms
²⁶⁸Hs	268.13216	~2 seconds
²⁶⁹Hs	269.13406	27 seconds
²⁷⁰Hs	270.13465	3.6 seconds
²⁷¹Hs	271.13766	~40 seconds
²⁷²Hs	272.13905	~40 seconds
²⁷³Hs	273.14199	~50 seconds
²⁷⁴Hs	274.14313	~1 minutes
²⁷⁵Hs	275.14595	0.15 seconds
²⁷⁶Hs	276.14721	~1 hours
²⁷⁷Hs	277.14984	40 minutes

Hassium Data

Atomic Structure

Atomic Radius:
Atomic Volume:
Covalent Radius:
Cross Section (Thermal Neutron Capture) Barns:
Crystal Structure:
Electron Configuration:

1s² 2s²p⁶ 3s²p⁶d¹⁰ 4s²p⁶d¹⁰f¹⁴ 5s²p⁶d¹⁰f¹⁴ 6s²p⁶d⁶ 7s²
Electrons per Energy Level: 2, 8, 18, 32, 32, 14, 2
Ionic Radius:
Filling Orbital:
Number of Electrons (with no charge): 108
Number of Neutrons (most common/stable nuclide): 157
Number of Protons: 108
Oxidation States:
Valence Electrons:

Chemical Properties

Electrochemical Equivalent:
Electron Work Function:
Electronegativity: N/A (Pauling); N/A (Allrod Rochow)
Heat of Fusion: kJ/mol
Incompatibilities:
Ionization Potential
- First:
Valence Electron Potential (-eV):

Physical Properties

Atomic Mass Average: 265
Boiling Point:
Coefficient of Lineal Thermal Expansion/K^-1: N/A
Conductivity

Electrical:
Thermal:
Description:

Man made radioactive metal.
Flammablity Class:
Freezing Point: see melting point
Heat of Vaporization: kJ/mol
Melting Point:
Physical State (at 20°C & 1atm):
Specific Heat:
Vapor Pressure:

Regulatory / Health

CAS Number
- 54037-57-9
NFPA 704
- Health:
- Fire:
- Reactivity:
- Special Hazard: Radioactive<
- OSHA Permissible Exposure Limit (PEL)
  - No limits set by OSHA
- OSHA PEL Vacated 1989
  - No limits set by OSHA
- NIOSH Recommended Exposure Limit (REL)
  - No limits set by NIOSH
- Levels In Humans:
  Note: this data represents naturally occuring levels of elements in the typical human, it DOES NOT represent recommended daily allowances.
  - Blood/mg dm^-3: nil
  - Bone/p.p.m: nil
  - Liver/p.p.m: nil
  - Muscle/p.p.m: nil
  - Daily Dietary Intake: nil
  - Total Mass In Avg. 70kg human: nil
Who / Where / When / How
- Discoverer: Peter Armbruster, Gottfried Munzenber, et al.
- Discovery Location: Darmstadt, Germany
- Discovery Year: 1984
- Name Origin:
  
  Latin "Hassias" meaning "Hess", the German state.
- Abundance:
  - Earth's Crust/p.p.m.: N/A
  - Seawater/p.p.m.: nil
  - Atmosphere/p.p.m.: N/A
  - Sun (Relative to H=1E¹²): N/A
- Sources:
  
  Synthetically prepared element. Only a small number of atoms have every been produced.
- Uses:
  
  None
- Additional Notes:
  
  In August of 1997 the International Union of Pure and Applied Chemistry announced the official naming of this element as Hassium

Transition Metals
Group	3 (IIIB)	4 (IVB)	5 (VB)	6 (VIB)	7 (VIIB)	8 (VIIIB)	9 (VIIIB)	10 (VIIIB)	11 (IB)	12 (IIB)
Period 4	21 Sc 44.95	22 Ti 47.86	23 V 50.94	24 Cr 51.99	25 Mn 54.93	26 Fe 55.84	27 Co 58.93	28 Ni 58.69	29 Cu 63.54	30 Zn 65.39
Period 5	39 Y 88.90	40 Zr 91.22	41 Nb 92.90	42 Mo 95.94	43 Tc 98.00	44 Ru 101.0	45 Rh 102.9	46 Pd 106.4	47 Ag 107.8	48 Cd 112.4
Period 6	57 La 138.9	72 Hf 178.4	73 Ta 180.9	74 W 183.8	75 Re 186.2	76 Os 190.2	77 Ir 192.2	78 Pt 195.0	79 Au 196.9	80 Hg 200.5
Period 7	89 Ac 227.0	104 Rf 261.0	105 Db 262.0	106 Sg 266.0	107 Bh 264.0	108 Hs 269.0	109 Mt 268.0	110 Ds 269.0	111 Rg 272.0	112 Uub 277.0

1s²
2s²	2p⁶
3s²	3p⁶	3d¹⁰
4s²	4p⁶	4d¹⁰	4f¹⁴
5s²	5p⁶	5d¹⁰	5f¹⁴
6s²	6p⁶	6d⁶
7s²