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Rare and Radioactive: Exploring the Fascinating Properties of Actinium

Actinium: A Radioactive Metal with Unique PropertiesActinium is a rare, highly radioactive metal with the chemical symbol Ac and atomic number 89. It belongs to the group of elements known as the actinides and has several isotopes, the most stable of which is actinium-227 with a half-life of approximately 21.8 years.

This article will provide an overview of how actinium was discovered, its characteristics, and where it can be found.

Definition and Characteristics of Actinium

Actinium is one of the rarest naturally occurring elements on Earth. It is a silvery-white metal that reacts with air, water, and acids.

Due to its high radioactivity, it poses a significant danger to human health and the environment. Actinium is a member of the actinide series, a group of chemical elements that share electronic configurations and chemical properties.

Actinium Isotopes

Actinium has several isotopes with varying half-lives. The most stable isotope is actinium-227, which undergoes alpha decay to form thorium-223.

Other isotopes like actinium-225 and actinium-228 decay through beta decay. Actinium-228 has a half-life of 6.13 hours, while actinium-225 has the shortest half-life of only 10 days.

Occurrence of Actinium

Actinium is a rare element found in uranium ore deposits. Uranium ore deposits are rocks that contain high concentrations of uranium and other elements like thorium, actinium, and radium.

These elements have radioactive isotopes that decay into other elements, which makes their concentration low. Due to its rarity, actinium is not commercially used or extracted.


Origin and Name of Actinium

The name actinium comes from the Greek word aktis, which means a beam or ray of light. The name is fitting since actinium emits alpha, beta, and gamma rays.

The French chemist, Andre Debierne, is credited with discovering actinium, and he named it after its ability to generate a “rayon-like radiation.”

Discovery of Actinium

Actinium was discovered in 1899 by Friedrich Otto Giesel while he was working with uranium-rich pitchblende ores. Giesel obtained a radioactive substance that was different from uranium.

The substance turned out to be actinium. The discovery of actinium helped to validate the periodic table, which had predicted the existence of a new element between thorium and uranium, both of which were known elements at the time.


In conclusion, actinium is a rare, highly radioactive metal with various isotopes, the most stable being actinium-227. It is found in uranium ore deposits and was discovered in 1899 by Friedrich Otto Giesel.

While not commercially utilized, actinium has significant scientific applications in radioactive labeling, chemical tracers, and medical radiography.

3) Classification and Position in the Periodic Table

Actinium is found in the seventh period of the periodic table, an unknown group of elements. Actinium is located in the d-block of the periodic table, which is the part of the periodic table consisting of transition metals.

The placement of actinium in the periodic table reflects its properties, which are similar to other transition metals like thorium and uranium.

To understand the placement of actinium on the periodic table, it is essential to understand how the table is organized.

The periodic table is arranged according to the electronic configuration of elements. Electronic configuration refers to the arrangement of electrons within an atom, including the number of electrons in each orbital and their spin.

The ordering of the elements follows a periodic pattern in which elements with similar electronic configurations and properties are arranged in a similar way. Actinium is located in period 7, which is the row of elements in the periodic table that contain electrons in the seventh principal energy level.

The position of actinium in the d-block reflects its electronic configuration, which is [Rn]6d1 7s2. This electronic configuration indicates that actinium has one valence electron in the 6d subshell.

4) Properties of Actinium

General Properties of Actinium

Actinium is a silvery-white, radioactive metal with an atomic mass of 227. It has a melting point of 1051C and a boiling point of 3197C.

The density of actinium is 10.07 g/cm3, which is similar to the density of other metals. At room temperature, actinium is solid, and it possesses metallic conductivity.

Chemical Properties of Actinium

Actinium has reactive chemical properties. It is highly flammable and oxidizes rapidly when exposed to air or water.

Actinium can exist in several oxidation states, including +2 and +3. The element has two valence electrons, and its electron configuration is [Rn]6d17s2.

The electronegativity of actinium is 1.1, which is relatively low, indicating that it is not highly attracted to electrons. The first ionization energy of actinium is 499 kJ/mol, indicating that it is easier to remove its outermost electron than other metals.

Atomic Data of Actinium

Actinium has an atomic number of 89, which means it has 89 protons in its nucleus. The number of electrons in a neutral atom of actinium is also 89.

The number of neutrons in actinium varies depending on the isotope. Actinium-227 has 138 neutrons, while actinium-225 has 136 neutrons.

The radius of an atom of actinium is approximately 195 picometers.


In conclusion, actinium is a highly radioactive metal with unique properties that stem from its position in the periodic table. Despite being a rare element, actinium has uses in specialized scientific applications such as radioactive labeling, chemical tracers, and medical radiography.

Actinium, like other rare earth elements, is of great interest to scientists due to its unique properties and potential uses in various fields.

5) Uses of Actinium

Actinium has both commercial and laboratory uses, thanks to its unique properties and high radioactivity that make it useful in various applications. Some of these applications include:

Alpha Rays: Actinium emits alpha rays, which are high-energy particles that can penetrate through solid materials.

These particles are used in smoke detectors to detect smoke particles. They are also used to generate electrical power in thermoelectric generators.

Neutron Generation: Actinium-227 is used to generate neutrons in nuclear reactors. Neutrons are used in the production of radioisotopes for medical and industrial applications.

Prostate Cancer Treatment: Actinium-225 is used in the treatment of prostate cancer. It is used in a targeted alpha therapy, which specifically targets cancer cells and minimizes damage to surrounding healthy tissue.

Commercial Applications: Actinium does not have many commercial applications due to its rarity and high cost of production. However, it is sometimes used in alloys with other metals for its radioactive properties.

Laboratory Research: Actinium is used as a radioactive tracer in medical and scientific research. It is also used in the analysis of geological samples to determine their age using the decay of actinium isotopes.

Health Hazards of Actinium

While actinium has its uses, it poses significant health hazards due to its high radioactivity. Accidental ingestion or inhalation of actinium can lead to deposition in bones and liver, causing significant health risks.

Actinium also poses a cancer risk due to its radioactive decay. Exposure to actinium, like any other radioactive material, can result in the development of cancer in humans.

6) Interesting Facts

Curie Connection and Other Facts About Actinium

Actinium has an interesting history and various unique properties that make it an intriguing element. Here are a few interesting facts about actinium:


Marie and Pierre Curie discovered actinium while studying a pitchblende sample that also contained radium and polonium. 2.

Actinium’s ionization potential is higher than any other known element. This is due to its small atomic radius and large number of protons.

3. Actinium is highly radioactive and is known to glow blue in the dark due to its radioactivity.

4. Actinium was first isolated in 1902 by Debierne and then independently in 1904 by Giesel.

5. Actinium is the second-heaviest element in the actinide series.

6. The atomic weight of actinium is 227, and its chemical symbol is Ac.

In conclusion, actinium is an intriguing element with unique properties and radioactive properties that make it useful in various applications.

Its high radioactivity also poses significant health hazards, requiring extreme caution in its handling and use. Its interesting history and potential scientific applications make it a fascinating element to study.

7) Cost of Actinium

Actinium is a rare and highly valuable element, which makes its production and commercial use an expensive endeavor. Due to its high radioactivity, handling actinium is highly technical, and its commercial-scale production remains a challenge.

Here is an overview of actinium’s production, availability, and cost:

Production of Actinium:

Actinium is produced in small quantities by laboratory methods that involve the irradiation of radium-226. The radium is irradiated in a nuclear reactor to generate actinium-227.

The actinium-227 is then chemically extracted from the radium targets using techniques like solvent extraction and ion exchange. The extracted actinium is then purified and packaged for sale.

Availablility of Actinium:

Actinium is not readily available in commercial quantities due to its rarity and high cost of production. The low availability of actinium makes it expensive and limits its commercial applications.

In contrast to other elements like gold and silver, which are widely available and more economically feasible for commercial use, actinium is one of the rarest elements on earth. Cost:

The cost of actinium is incredibly high due to its rarity, and the cost is often determined by the specific isotope required.

Depending on the isotope and the level of radioactivity required, the cost of actinium can vary widely. Generally, actinium is sold on a per-milligram basis, with prices ranging between a few thousand and tens of thousands of dollars per milligram.

Due to the high cost of actinium, its commercial applications have been limited. The use of actinium in the medical industry for alpha radiation therapy is one of its primary commercial applications.

Despite its expensive nature, actinium has been steadily gaining interest in the scientific and medical industries due to its unique properties and therapeutic potential.


Actinium is a rare and valuable element that is difficult and expensive to produce commercially. The low availability and high cost of actinium limit its applications outside of specialized scientific and medical fields.

Nevertheless, the unique properties of actinium make it a valuable element in these fields, and it holds considerable potential for future research and therapeutic applications. In conclusion, actinium is a rare radioactive metal with unique properties that make it valuable in scientific and medical applications.

Despite its high cost and limited availability, actinium is used in targeted alpha therapy for prostate cancer treatment and as a source of alpha rays in smoke detectors and neutron generation. However, the health hazards associated with actinium’s high radioactivity require proper handling and caution.

Actinium’s intriguing history, connection to Marie Curie, and its glowing properties add to its allure. While actinium is not commercially widely used, its potential for future research and therapeutic applications is promising.


1) What is actinium? Actinium is a rare and highly radioactive metal with the chemical symbol Ac and atomic number 89.

2) How is actinium used commercially? Actinium is used in targeted alpha therapy for prostate cancer, in smoke detectors, and in generating neutrons in nuclear reactors.

3) Is actinium readily available? No, actinium is not readily available commercially due to its rarity and high cost of production.

4) What are the health hazards of actinium? Accidental ingestion or inhalation of actinium can lead to the deposition of the element in bones and liver, posing a significant health risk.

Actinium’s radioactive decay can also increase the risk of developing cancer. 5) What is the cost of actinium?

The cost of actinium is high, varying depending on the isotope required. Prices range from a few thousand to tens of thousands of dollars per milligram.

6) What are some interesting facts about actinium? Actinium was discovered by Marie and Pierre Curie, it glows blue in the dark due to its radioactivity, and it has the highest ionization potential of any known element.

In summary, actinium’s rarity, high cost, and radioactivity make it a valuable but limited element. Its applications in targeted therapy and scientific research hold promise, but proper handling and caution are crucial due to its health hazards.

Actinium’s unique properties and intriguing history make it an element of fascination in scientific and medical fields.

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