Actinium is a radioactive metal with the symbol Ac and atomic number 89. It was discovered in 1902 by Friedrich Oskar Giesel. It is the first element in the actinide series on the periodic table. It is found in uranium ores and is highly radioactive. Actinium's most common use is in the production of neutrons for research.
In this article, we will learn about the element Actinium in detail, including its discovery, properties, uses, and effects.
Table of Content
Actinium Element Information
Here is some basic information on the element Actinium of the periodic table.
| Property | Description |
|---|---|
| Symbol | Ac |
Category | Actinide |
Period | 7 |
Block | f-block |
| Atomic Number | 89 |
| Atomic Mass | 227 atomic mass units (amu) |
| State at 20°C | Solid |
| Electron Configuration | [Rn] 6d1 7s2 |
| Common Isotopes | Actinium-227 |
What is Actinium?
Actinium is a rare and highly radioactive element. It is denoted by the symbol Ac and has an atomic number of 89.
Actinium is the first element of the actinide series in the periodic table. It occurs naturally in uranium and thorium ores. It is more than 150 times less abundant than uranium. Actinium glows pale blue in the dark due to its intense radioactivity.
Actinium Discovery
Actinium was discovered in 1899 by the German chemist Friedrich Oskar Giesel. He initially isolated it as a substance that emitted intense radiation, which glowed in the dark. Giesel named it "Actinium". It came from the Greek word "aktinos," meaning ray, reflecting its strong radiative powers.
In 1902, the famous French chemist André-Louis Debierne independently discovered actinium. He described it as a substance similar to titanium and (incorrectly) thorium. Later analysis confirmed that both Giesel and Debierne had discovered the same element.
Actinium Symbol
The symbol of actinium element is shown below:
Properties of Actinium
Properties of Actinium can be studied in following two categories
- Physical Properties of Actinium
- Chemical Properties of Actinium
Let's learn them in detail
Physical Properties of Actinium
These are some of the physical properties of Actinium:
| Property | Description |
|---|---|
| State at 20°C | Solid |
| Color/Appearance | Silvery-white, glowing pale blue in the dark |
| Melting Point | 1050°C |
| Boiling Point | 3200°C |
| Density | Approximately 10 g/cm³ at room temperature |
| Radioactivity | Highly radioactive |
Malleability | High |
Ductility | Low |
Conductivity | Good electrical conductor |
Crystal Structure | Face-centered cubic (fcc) |
Magnetic Properties | Paramagnetic |
Chemical Properties of Actinium
Actinium is highly reactive as it comes from the actinide series. Its electropositive nature and radioactive decay properties influence its various reactions.
Reactivity with Oxygen
- Actinium reacts with oxygen quickly when exposed to air.
- It forms Actinium(III) oxide, represented by the formula Ac2O3.
- Actinium tarnishes in air due to oxidation. It forms a white oxide coating that protects deeper layers from further oxidation.
4Ac + 3O2 → 2Ac2O3
Reaction with Water
- Actinium does not react noticeably with cold water.
- It reacts with steam, forming Actinium(III) hydroxide.
- The reaction can be written as:
2Ac + 6H2O → 2Ac(OH)3 + 3H2
Reactivity with Acids
- Actinium dissolves in acids.
- Actinium dissolves easily in acids such as hydrochloric acid and sulfuric acid. When Actinium reacts with hydrochloric acid, it forms actinium(III) chloride, releasing hydrogen gas in the process. The chemical equation is given by :
Ac + 6HCl → 2AcCl3 + 3H2
- Actinium also reacts with sulfuric acid to produce actinium(III) sulfate and hydrogen gas. The equation for this reaction is:
2Ac + 3H2SO4 → Ac2(SO4)3 + 3H2
Reaction with Halogens
Actinium reacts with halogens, forming halides.
- It reacts vigorously with fluorine to form Actinium(III) fluoride. The chemical reaction is as follows: 2
Ac +3F2 → 2AcF3
In this reaction, Actinium fluoride (AcF3) is produced as a white solid.
- Actinium also reacts with chlorine gas to produce Actinium(III) chloride. The equation for this reaction is:
2Ac + 3Cl2 → 2AcCl3
Actinium chloride (AcCl3) forms as a white solid.
Uses of Actinium
Here are some of the most common uses of Actinium
- Actinium-225 is used in medicine for targeted alpha therapy (TAT).
- This isotope is effective in treating cancers, such as leukemia and lymphoma.
- It targets cancer cells without harming the surrounding healthy tissue.
- Actinium is also used in neutron emitters for research in neutron radiography.
- Researchers utilize it to study the structure of materials due to its neutron emission.
- Actinium's isotopes are used7 in the production of neutrons in research reactors.
Effects of Actinium
Actinium is highly radioactive, which makes handling it extremely hazardous. Exposure to it has many health and environmental risks.
Environmental Effects of Actinium
- Actinium's radioactivity can contaminate soil and water bodies.
- It poses risks to wildlife, potentially causing mutations or death.
- Contaminated environments may remain unsafe for long periods due to Actinium's long half-life.
- Handling and disposal require strict regulations to prevent accidental releases.
- Plants and microorganisms may absorb Actinium, entering the food chain.
- Cleanup of Actinium contamination is complex and costly, requiring specialized techniques.
Health Effects of Actinium
- Exposure to Actinium can cause acute radiation sickness.
- Symptoms include nausea, vomiting, fatigue, and loss of hair.
- Long-term exposure significantly raises the risk of cancer.
- Actinium emits gamma rays and neutrons, which penetrate tissues deeply.
- Protective measures are crucial for those handling Actinium to avoid exposure.
- Proper storage and minimal handling reduce risks of accidental poisoning.
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