Hassium

Hassium is a chemical element with the atomic number 108 and symbol Hs. It belongs to group 8 and period 7 of the periodic table of elements. It is a transition metal which is solid at room temperature. This element is one of the densest elements due to the presence of 108 protons in its nucleus. The atomic weight of an atom of the Hs element is 269. The electronic configuration of this radioactive metal is [Rn] 5f146d67s2. Most of the isotopes of Hs are unstable and have very short lives. The basic information of this radioactive element is as follows. 

Basic Information of Radioactive Element

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The above image shows the position of Hassium in the periodic table. 

Discovery and Naming

Chemists from different regions tried to make several attempts to synthesise Hassium before its official discovery. In 1984, the German scientists including Peter Armbruster, Gottfried Munzenber and co-workers claimed to produce this element at GSI. At the same time, the Russian scientists also claimed to synthesise this element. In 1993, the report formed by the International Union of Pure and Applied Chemistry and IUPAP assigned the major credit to a German scientist. According to them, the report made at GSI was more conclusive as compared to the Russian scientists. 

Before the official discovery of Hassium, chemists referred to it as element 108 or eka-osmium. The IUPAC and IUPAP gave the official credit to German scientists due to their detailed work. Peter Armbruster and co-workers proposed the name Hassium for this element. The name Hassium comes from the Latin word Hess of Hess, where the scientists produced this element for the first time. In 1997, the IUPAC finally named the element 108 as Hassium. 

Occurrence

Hassium has not been observed in nature until now. The reason behind it is that the half-lives of all known isotopes of this element are too short. Hence, no primordial hassium could have survived to present from the beginning of this universe. However, there can be some isotopes of this element which may have longer half-lives. It means that they might be present on earth in trace quantities. Hassium was first synthesised by cold fusion of lead-208 with iron-58 nuclei by the following reaction. 

208Bi + 58Fe → 265Hs + 1n

Hs element decays very quickly. Hence, scientists had minimal quantities of Hs until now. A Russian scientist Victor Cherdyntsev also claimed to discover Hassium occurring naturally. However, he couldn't verify his statement.  

Properties of Hassium

Due to the limited and expensive production of Hs, many properties of this element remain unknown. Only some predictions are available according to the various calculations made by chemists. Scientists believe that this radioactive element is a dense solid metal at room temperature. It must have a shiny and metallic appearance. Various calculations made by chemists suggest that it can be the heaviest element in group 8. The predicted density of this transition metal is 41g/cm3 at standard temperature and pressure. 

Hs must crystallise in hexagonal close-pack structure as per the predictions. The expected atomic radius of this metal is around 126pm. The predicted electronic configuration of Hs+ ion is [Rn] 5f14 6d57s2 due to relativistic de-stabilisation of the 6d orbital and stabilisation of the 7s orbital. Instead of a 7s electron, the Hs+ ion gives up 6d electron which is opposite in its lighter homologues. 

Hs is present in the 6d series of transition metals as the sixth metal. Hence, scientists predicted that it must have similar properties like the platinum group metals. The expected oxidation states of Hassium according to its electronic configuration are +8, +6, +4, +3, and +2. Hs is also likely to react with oxygen to give volatile tetraoxide. 

Isotopes

Hassium has no naturally occurring or stable isotopes. Currently, scientists had synthesised twelve isotopes of Hs, and all of them are radioactive. The mass number of these isotopes of Hs element ranges from 263 to 277. All known isotopes of Hs except Hassium-277 decay predominantly through alpha decay. Hassium-277 is the only known isotope of Hs which undergoes spontaneous fission. The half-lives of all the isotopes of Hs are too short, even less than 22 seconds. The most stable isotope of Hs is 269Hs which has a half-life of around 16 seconds. 

Scientists have a particular interest in isotope 270Hs due to its magic number of nuclear stability. In 1991, Zygmunt Patyk and Adam Sobiczewski predicted some interesting things. According to them, the neutron magic number for deformed nuclei (non-spherical nuclei) is 162, and the proton magic number for it is 108. Hence, the nucleus of this isotope of Hs has doubly magic which leads to low decay energy.