Ununoctium is the temporarily given IUPAC name which helps to identify the chemical element. Scientists know very little about it; however, it is considered as super heavy element with an atomic number of 118. The atomic number and atomic mass of the discovered element is the highest.

What is Ununoctium?

The former name of element 118 is Ununoctium, which is also known as the eka-radon. Ununoctium is a temporary IUPAC name for the synthetic element and it is super heavy non-metal. It is not free in the planet and hence, called as the artificial element. The term ununoctium is derived from a Latin word, which means one-one-eight.

Figure 1: Structure of Ununoctium

anonymous, Electron shell 118 ununoctium, CC BY-SA 2.0 UK

The ununoctium is known as Oganesson in the present time presented with the symbol of Og. The name Oganesson is given to pay respect and honour to the scientist Prof. Yuri Oganessian, who was a nuclear scientist and played a crucial role in the discovery of the element. It belongs to the group of noble gas in group of 18.

Ununoctium is an unstable and radioactive atomic nucleus and in the periodic table, it is the last element present in the 7th period. It belongs to the noble gas group and is a p–block element. It shows almost same characteristics like the other elements of the same group.

Discovery of Ununoctium

Ununoctium was discovered by the joint engagement of American and Russian scientists. After two failed attempts, they were successful in the discovery of ununoctium. It was discovered at the Lawrence Livermore National Laboratory.

In the year 1999, they published a paper with an announcement of the discovery. It was published with the name of element 118; however the result of the experiment cannot be replicated. Hence, in 2006, it was again officially announced by the Dubna team and by the Lawrence Livermore National Laboratory team. The date was 19th July, 2002, when the ununoctium was finally discovered. In the initial stage, it was given the name of ununoctium, later on, it was named as Oganesson.

Properties of Ununoctium

The physical and chemical properties of ununoctium are not completely known to the scientist, these have not been thoroughly studied. For example, the electronic configuration, density, and phase are still unknown. However, a few properties are known, such as, having the highest atomic mass compared with all the discovered elements.

The estimated density of ununoctium is between 4.9–5.1 g/cm3. The boiling point is 80±30°C, however, the melting point is yet unknown. Other than that, the value of the ionic radius, the presence of isotopes, and Van Der Waals radius is also unknown. The energy of first ionisation is 839.4 kJ/mol and has the electronic shell of [Rn] 5f14 6d10 7s2 7p6. It is toxic because of its radioactivity. It has one isotope which can survive with a half-life of about 0.89 milliseconds.

Source of Ununoctium

Ununoctium is produced with the help of atoms of californium-249 and calcium-48. As this process needs bombardment, it should be done only under expert scientists’ observation. The result of this process is formation of an isotope of ununoctium-294 and along with 3 free neutrons. The first discovery process of ununoctium took almost 1080 hours to complete and as a result, it gives 3 atoms.

Use of Ununoctium

Ununoctium does not have any specific kind of use in human life. It is only used in laboratories for research purposes. Biological usage is still unknown of this element. It can be harmful to organisms because due to its radioactivity nature; however, it should be studied more. It is a super heavy element and unstable in nature, however, it has commercial applications.


Ununoctium is a chemical element, which is majorly unknown. It is considered in a form of a colourless gas and it belongs to the group of the noble gas. As it exists only for a free millisecond, it is hard to identify and even harder in the identification of the chemical properties. However, its basic nature is radioactive and there is no such use in daily life.

Until now, 118 elements have been discovered in this planet and among them only 94 elements are found naturally and the rest of them are artificially made, ununoctium is one of them.


Q1. What does Ununoctium look like?

Ans. Ununoctium is a chemical, whose chemical properties are still unknown. However, it is believed that Ununoctium is present in a form of a colourless gas. This element can be produced to study further the chemical property; otherwise, it is tough to identify the chemical property because it only exists for milliseconds.

Q2. What is the rarest element present on this planet?

Ans. The rarest element present on this planet is believed the astatine. At a certain time, a very less amount is produced naturally, which is approximately 25g. In 1889s, it was first predicted and 70 years later it was discovered.

Q3. What is the heaviest element on this earth?

Ans. It is believed that uranium is the heaviest element present on this earth. It has an atomic number of 92, which refers to the number of protons present in the atom’s nucleus.

Q4. What is the heaviest non-metal?

Ans. The heaviest non-metal is iodine and its mass is 126.9. It is a non-metallic element, which is solid and dark-grey in colour or sometimes may be in purple black appearance.

Updated on: 17-Apr-2023


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