Hassium is a synthetically produced chemical element with an atomic number of 108 in the periodic table. Due to its atomic weight which is greater than 92, this radioactive substance is classified as a transuranium element. The eight-valent element also belongs to the family of transition metals. 

Fact Box

Chemical and Physical Properties of Hassium

The symbol in the periodic table of elements: Hs

Atomic number: 108

Atomic weight (mass): [269]

Group number: 8 (Transition metals)

Period: 7

Color: (Assumed) silvery white or metallic gray

Physical state: (Presumably) a solid metal

Half-life: From 760(40) milliseconds to 12 minutes

Electronegativity according to Pauling: Unknown

Density: Unknown

Melting point: Unknown

Boiling point: Unknown

Van der Waals radius: Unknown

Ionic radius: [126pm]

Isotopes: 15

Most characteristic isotope:

Electronic shell: [Rn] 5f146d67s2 

The energy of the first ionization: Unknown

The energy of the second ionization: Unknown

Discovery date: In 1984 by Peter Armbruster, Gottfried Münzenber and co-workers at GSI in Darmstadt, Germany

Hassium is a man-made chemical element that is classified in the periodic table under the symbol Hs, with the atomic number 108, and electron configuration [Rn] 5f146d67s2. Hassium atoms have the following shell structure: This super-heavy element belongs to the family of transuranium elements, with an expected atomic radius of 126 pm.  

Since hassium is a highly radioactive substance and hasn’t been thoroughly studied so far, it is postulated that its chemical properties are similar to those of the elements osmium and ruthenium. It’s also assumed that hassium may be silvery white or metallic gray in color. Also, it’s assumed that it would be able to show excellent catalytic properties and exceptional resistance to a chemical attack.            

How Was Hassium Discovered?

In 1978, the first attempt for creating the new radioactive element 108 took place at Russia’s Joint Institute for Nuclear Research (JINR) in Dubna. Here, a team of scientists led by Yuri Oganessian and Vladimir Utyonkov attempted a bombardment of radium with calcium, which resulted in a hassium-270 isotope. Five years later, Oganessian and Utyonkov led the team into another scientific victory, by succeeding to produce three more atoms of hassium.

Oganessian and Utyonkov’s Contribution

Namely, they bombarded bismuth with manganese which resulted in the hassium-263 isotope. Next in their research, the scientists tried to bombard californium with neon. This time, their efforts produced the hassium-270 isotope. Finally, by bombarding lead with iron, they made the hassium-265 isotope. However, the scientific evidence on the obtained forms of hassium was not satisfying. 

Armbruster and Münzenbergg’s Contribution

In 184, Peter Armbruster (1931) and Gottfried Münzenberg (1940) made a scientific attempt to reproduce the production of the first isotope of the highly radioactive hassium. They tried to contribute to the study of the new element with more reliable scientific evidence and the two German physicists attempted to trigger a fusion reaction together with their team of scientists at Germany’s Gesellschaft für Schwerionenforschung (GSI) – the Heavy Ion Research Laboratory in Darmstadt, Hesse. 

By bombarding atoms of an isotope of lead (208Pb) with ions of an iron isotope (58Fe) in a linear accelerator, the nuclear physicists led by Armbruster and Münzenberg succeeded in producing the first isotope of hassium (265Hs) and a free neutron, thus providing more reliable scientific evidence. This allowed them the privilege to name the element 108 as hassium. 

How Did Hassium Get Its Name?

The name of element 108 was derived from the Latin name ‘Hessen’ (Hassias). It refers to the German state of Hesse – the country where the Heavy Ion Research Laboratory is located and where the first atom of hassium was produced. However, the IUPAC didn’t approve the name of element 108 until the 13th anniversary of hassium’s discovery. 

Namely, the first IUPAC recommendation was for element 108 to be named ‘unniloctium’, which was contrary to the suggestion of the German team who stood behind the new element. In 1994, IUPAC took a stand that it would’ve been a good idea to honor the Nobel-prize winning chemist Otto Hahn by naming this element ‘hahnium’ after him. This was also proposed for element 104, today known as ‘dubnium’. 


The Honor of Discovering an Element

Finally, in 1997 IUPAC agreed on the name ‘hassium’ after the homeland of the discoverers of the element 108. In this way, the team employed at the Gesellschaft für Schwerionenforschung (GSI) led by Peter Armbruster and Gottfried Münzenberg was honored for their contributions to the world of science. 

Where Can You Find Hassium?

The free elemental form of hassium does not occur naturally in Earth’s core since it’s a synthetic element. Also, due to its enormous radioactivity, as well as the limited capacities and high costs of its production, only a small quantity of this substance has been made. 

Hassium in the Everyday Life

Since there are only a few atoms of hassium produced, this element has so far been used only for scientific researches. 

How Dangerous Is Hassium?

The unstable electron configuration of hassium leaves no room for current studies on its possible hazardous effects on human health. However, its radioactivity could possibly damage cell mechanisms, leading to their mutation and possibly fatal outcomes upon exposure to larger quantities of hassium.  

Environmental Effects of Hassium

Despite its high radioactivity, there are no significant environmental hazards imposed by hassium. This is due to the fact that the isotopes of this transuranium element have an extremely short half-life. 

Isotopes of Hassium

There are no stable or naturally occurring isotopes of hassium. Among the fifteen isolated hassium isotopes with mass numbers ranging from 263 to 277, hassium-277 is the most stable isotope that stands out among them with the longest half life of around 12 minutes.

Almost all of them go through the alpha decay process, apart from the hassium-277 isotope that undergoes a spontaneous fission. 



[n 1]

ZNIsotopic mass (Da)


[n 2][n 3]




[n 4]




Spin and



[n 5]

Excitation energy
263Hs108155263.12856(37)#760(40) µsα259Sg3/2+#
264Hs108156264.12836(3)540(300) µsα (50%)260Sg0+
SF (50%)(various)
265Hs108157265.129793(26)1.96(0.16) msα261Sg9/2+#
265mHs300(70) keV360(150) µsα261Sg3/2+#
266Hs[n 6]108158266.13005(4)3.02(0.54) msα (68%)262Sg0+
SF (32%)[3](various)
266mHs1100(70) keV280(220) msα262Sg9-#
267Hs108159267.13167(10)#55(11) msα263Sg5/2+#
267mHs[n 7]39(24) keV990(90) µsα263Sg 
268Hs108160268.13187(30)#1.42(1.13) sα264Sg0+
269Hs[n 8]108161269.13375(13)#16 sα265Sg9/2+#
270Hs108162270.13429(27)#10 sα266Sg0+
271Hs108163271.13717(32)#~4 sα267Sg 
273Hs[n 9]108165273.14168(40)#510 ms[4]α269Sg3/2+#
275Hs[n 10]108167275.14667(63)#290(150) msα271Sg 
277Hs[n 11]108169277.15190(58)#11(9) msSF(various)3/2+#

Source: Wikipedia

List of Hassium Compounds 

According to the chemical calculations and predictions, any of the hassium compounds would have had a stable oxidation state of +8. The less likely projections are the lower stable +6, +4, +3, and +2 oxidation states of hassium. 

5 Interesting Facts and Explanations

  1. The heaviest chemical element in the periodic system, oganesson, has been named after the Russian scientist who led the first team that attempted producing hassium. 
  2. Oganessian is also the scientist behind the invention of the cold fusion technique, by which  nuclear reaction is triggered at room or near room temperature. 
  3. Apart from hassium, the transuranium family of elements also consists of neptunium, plutonium, americium, curium, berkelium, californium, einsteinium, fermium, mendelevium, nobelium, lawrencium, rutherfordium, dubnium, seaborgium, bohrium, meitnerium, darmstadtium, roentgenium, copernicium, nihonium, flerovium, moscovium, livermorium, oganesson, and tennessine
  4. The transuranium elements with an atomic mass up to 100 are produced by the capture of neutrons, while the transuranium elements with an atomic mass higher than 100 are made by the bombardment of transuranium target-elements with particles of the lighter elements. 
  5. Due to the unstable electron configuration of their large nucle, the transuranium elements are highly radioactive with an extremely short half-life of their isotopes.