Hassium is a synthetic element that was discovered in 1978. It is a highly radioactive and unstable element.

History and Discovery

Hassium is a chemical element.It has been named unniloctium and eka-osmium.It has the symbol Hs.It has the atomic number 108. It is a transuranium element. Hassium is a radioactive element that does not exist in nature. Hassium is a metal belongs to a group of elements called the transition metals. These metals make up the central block of the periodic table and have similar properties and characteristics, such as.

According to the Mendeleev’s nomenclature of undiscovered elements, hassium was named as eka-osmium or element-108. The efforts to create hassium started in 1978, when a team of scientists led by Yuri Oganessian at The Joint Institute for Nuclear Research (JINR), Dubna, Russia [1]. They did not achieve the desired results. Later in 1984, Peter Armbruster and Gottfried Münzenberg who worked at the Gesellschaft für Schwerionenforschung (GSI; Institute for Heavy Ion Research) Germany, bombarded a lead target with nuclei of iron and produced three atoms the 108 element, hassium-265. The element was named hassium after the Hassia, which is the Latin name for German state Hesse where GSI institute was located. The name was suggested by Peter Armbruster in 1992. The International Union of Pure and Applied Chemistry approved the name hassium in 1997. Its symbol is Ha.


Periodic Table ClassificationGroup 8
Period 7
State at 20CSolid (predicted)
ColorSilvery (predicted)
Electron Configuration[Rn] 5f14 6d6 7s2
Electron Number108
Proton Number108
Electron Shell2, 8, 18, 32, 32, 14, 2
Density41.00 g.cm-3 at 20°C (predicted)
Atomic number108
Atomic Mass277.00 g.mol -1
Electronegativity according to Paulingn/a



Hassium is an artificial element and does not exist in nature. Around a hundred atoms of hassium have been synthesized till date [2].

Physical Characteristics

Hassium is a silvery metal and predicted to be a solid under normal conditions. It is expected to have a density of around 40.7 g/cm3, which make it the heaviest of all known 118 known elements. The amount of hassium produced so far and the short half-life of hassium has made it difficult to carry out analysis of its physical and chemical characteristics.


Chemical Characteristics

The chemical characteristics of hassium are not well studied yet. It is predicted to chemically resemble osmium, ruthenium and iron. It is expected to readily react with oxygen and form a tetroxide that is highly volatile. Hassium has been placed in the 6d series of transition metal. It is a member of the group 8 and 7th period of the periodic table. The most stable oxidation state of hassium has been proposed to be +8.

Hassium Element

Significance and Uses

  • Hassium is used for research purposes.

Health Hazards

Hassium is a radioactive element and requires special precautions with handling and storage.

Isotopes of Hassium

There are twelve isotopes of hassium, that range in atomic masses from 263 to 277. They are unstable and unnatural. Most of the radioisotopes decay through the emission of alpha particles while some undergo spontaneous fission [3]. The most stable isotope is hassium-270 is which half-life of around tensecondsd.


[1]. Oganessian, Yu. Ts.; Ter-Akopian, G. M.; Pleve, A. A.; et al. (1978). Опыты по синтезу 108 элемента в реакции 226Ra + 48Ca [Experiments on the synthesis of element 108 in the 226Ra+48Ca reaction] (PDF) (Report) (in Russian). Joint Institute for Nuclear Research. Retrieved 8 June 2018.

[2]. Emsley, John (2011). Nature’s Building Blocks: An A-Z Guide to the Elements (New ed.). New York, NY: Oxford University Press. p. 215–7. ISBN978-0-19-960563-7.

[3]. Office of Science, Nations Work Together to Discover New Element,.

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About Hassium

Hassium, atomic number 108, is a synthetic transactinide element. Though early experiments in the late 1970's by the Russian research team of Turi Oganessian and Vladimir Utyonkov at the Joint Institute for Nuclear Research, it is unclear from available data whether they were successful. The official discovery of Hassium has been credited to the German research team of Peter Armbruster and Gottfried Munzenberg at the Institute for Heavy Ion Research in 1984. The naming of hassium was a contentious one, and wasn’t resolved until 1997, when the IUPAC gave in to the discovering team's desire to name the element for the German state of Hessen, where the Institute for Heavy Ion Research (GSI) is located.

Though hassium's instability has precluded extensive study of its chemical properties, many of these can be predicted from its location on the periodic table. As a member of the group 8 elements, it is expected to have properties similar to those of the platinum group elements, especially its closest homologue osmium. Notably, hassium is predicted to have a density higher than any of the known elements, nearly double the density of osmium, which has the highest density that has been measured. Like many other unstable synthetic elements, hassium is studied extensively in basic science research settings, but lacks any practical applications.

Hassium Properties

Hassium is a D-Block, Group 8, Period 7 element. The number of electrons in each of hassium's shells is 2, 8, 18, 32, 32, 14, 2 and its electron configuration is [Rn] 5f146d6 7s2. In its elemental form, hassium's CAS number is 54037-57-9. Hassium's appearance is unknown but it is suspected to be silvery white or metallic grey in color. Hassium is a synthetic element that is not present in the environment. Little is known about the element and it has no known uses. Hassium was first created in 1984 by a team headed by Peter Armbruster and Gottfried Münzenber at the Heavy Ion Research Laboratory in Darmstadt, Germany. Its name is derrived from the Latin word 'Hassias' meaning 'Hess,' after the German state.

Hassium information, technical data, properties, and other useful facts are detailed below. Scientific facts, such as the atomic structure and ionization energy are included.



Atomic Number:108
Atomic Weight:277
Element Category:transition metal
Group, Period, Block:8, 7, d
Color:unknown (presumably metallic/ silvery white/ gray)
Other Names:Hassio
Melting Point:N/A
Boiling Point:N/A
Density:41 kg·cm3 (predicted)
Liquid Density @ Melting Point:N/A
Density @ 20°C:N/A
Density of Solid:28600 (predicted) kg·m3
Specific Heat:N/A
Superconductivity Temperature:N/A
Triple Point:N/A
Critical Point:N/A
Heat of Fusion (kJ·mol-1):N/A
Heat of Vaporization (kJ·mol-1):N/A
Heat of Atomization (kJ·mol-1):N/A
Thermal Conductivity:N/A
Thermal Expansion:N/A
Electrical Resistivity:N/A
Tensile Strength:N/A
Molar Heat Capacity:N/A
Young's Modulus:N/A
Shear Modulus:N/A
Bulk Modulus:N/A
Poisson Ratio:N/A
Mohs Hardness:N/A
Vickers Hardness:N/A
Brinell Hardness:N/A
Speed of Sound:N/A
Pauling Electronegativity:N/A
Sanderson Electronegativity:N/A
Allred Rochow Electronegativity:N/A
Mulliken-Jaffe Electronegativity:N/A
Allen Electronegativity:N/A
Pauling Electropositivity:N/A
Reflectivity (%):N/A
Refractive Index:N/A
Electron Configuration:[Rn] 5f146d6 7s2
Atomic Radius:126 pm (estimated)
Atomic Radius,
non-bonded (Å):
Covalent Radius:134 pm (estimated)
Covalent Radius (Å):1.34
Van der Waals Radius:N/A
Oxidation States:8, 6, 5, 4, 3, 2 (predicted)
Phase:Solid (predicted)
Crystal Structure:N/A
Magnetic Ordering:N/A
Electron Affinity (kJ·mol-1)Unknown
1st Ionization Energy:733.3 kJ·mol-1(estimated)
2nd Ionization Energy:1756.0 kJ·mol-1(estimated)
3rd Ionization Energy:2827.0 kJ·mol-1(estimated)
CAS Number:54037-57-9
EC Number:N/A
MDL Number:N/A
Beilstein Number:N/A
SMILES Identifier:N/A
InChI Identifier:N/A
InChI Key:N/A
PubChem CID:N/A
ChemSpider ID:N/A
Earth - Total:N/A
Mercury - Total:N/A
Venus - Total:N/A
Earth - Seawater (Oceans), ppb by weight:N/A
Earth - Seawater (Oceans), ppb by atoms:N/A
Earth - Crust (Crustal Rocks), ppb by weight:N/A
Earth - Crust (Crustal Rocks), ppb by atoms:N/A
Sun - Total, ppb by weight:N/A
Sun - Total, ppb by atoms:N/A
Stream, ppb by weight:N/A
Stream, ppb by atoms:N/A
Meterorite (Carbonaceous), ppb by weight:N/A
Meterorite (Carbonaceous), ppb by atoms:N/A
Typical Human Body, ppb by weight:N/A
Typical Human Body, ppb by atom:N/A
Universe, ppb by weight:N/A
Universe, ppb by atom:N/A
Discovered By:Peter Armbruster and Gottfried Münzenber
Discovery Date:1984
First Isolation:N/A

Hassium Atom

Hassium Isotopes

Hassium (Hs) is an artificial element. Like all artificial elements, it has no stable isotopes.

Hassium Facts

NuclideIsotopic MassHalf-LifeMode of DecayNuclear SpinMagnetic MomentBinding Energy (MeV)Natural Abundance
(% by atom)
263Hs263.12856(37)#1# msa to 259Sg7/2+#N/A1891.72-
264Hs264.12839(5)540(300) µsa to 260Sg; SF 0+N/A1899.8-
265Hs265.13009(15)#2.1(3) ms [2.0(+3-2) ms]a to 261Sg; SF 9/2+#N/A1898.56-
266Hs266.13010(31)#2.7(10) ms [2.3(+13-6) ms]a to 262Sg0+N/A1906.64-
267Hs267.13179(11)#32(15) msa to 263Sg; SF 3/2+#N/A1914.72-
268Hs268.13216(44)#2# sa to 264Sg0+N/A1922.8-
269Hs269.13406(13)#27(17) sa to 265SgN/AN/A1930.88-
270Hs270.13465(31)#3.6(+8-14) sa to 266Sg0+N/A1938.96-
271Hs271.13766(36)#40# sa to 267SgN/AN/A1947.03-
272Hs272.13905(62)#40# sUnknown0+N/A1955.11-
273Hs273.14199(89)#50# sa to 269Sg(3/2+)#N/A1953.88-
274Hs274.14313(70)#1# minUnknown0+N/A1961.95-
275Hs275.14595(77)#0.15(+27-6) sa to 271SgN/AN/A1970.03-
276Hs276.14721(89)#1# hUnknown0+N/A1978.11-
277Hs277.14984(78)#40(30) min SF3/2+#N/A1986.19-