What is Barium?
Barium is a soft, silvery alkaline earth metal which is highly reactive in nature, due to its high reactivity it is never found in nature as a free element. Barium has atomic number 56 and is represented by the symbol Ba. Barium is the fifth element in Group 2 of the periodic table. The most common compounds of Barium are Barite and Witherite. Barium is never found in the free state but combines with sulfur, carbon, or oxygen.
Properties of Barium
Let us discuss the physical and chemical properties of Barium.
Physical Properties of Barium
Barium is a soft, silvery-white metal with a pale yellow shade and has Ba as its symbol. It has a medium specific-weight and is a very good conductor of electricity. It is difficult to purify Barium so, most of its properties are yet to be determined.
When Barium is kept at room temperature, it forms a cubic structure, It is a very soft metal and expands rapidly on heating. Barium element has a melting point of 1000 K or 730 °C or 1,340 °F whereas the boiling point of Barium is 2170 K or 1900 °C or 3450 °F.
Chemical Properties of Barium
The following table depicts the chemical properties of Barium.
History and Discovery of Barium
During the early middle ages, scientists knew about a few Barium minerals and were attracted to them as Barium minerals would glow for years on exposure to light. As the stones of Barium minerals were found near Bologna, Italy, they were named as “Bologna stones.” Later in the year 1774, a scientist named Carl Wilhelm Scheele discovered that Barium minerals contain an element, but he was not able to isolate Barium.
Occurrence of Barium
Barium never occurs in the free state on earth, and it is always found in a combined form with sulfur, carbon or oxygen. Barium is found 0.0425% on earth’s crust, and 13 μg/L in seawater. The only commercial source for obtaining Barium is Baryte which is Barium sulphate. Other sources for obtaining barium is witherite which is Barium carbonate.
Production of Barium
Barium is produced in various parts of the world such as China, India, Morocco, US, Turkey etc. In the year, 2011, China was the leading producer of Barium. Barium is produced using various methods and processes.
The barium ore is mined, washed, crushed and is separated from quartz then it is reduced to barium sulfide using carbon. The water-soluble barium sulfide is used to make various compounds of barium such as Barium sulphate, barium nitrate or barium carbonate. These compounds can be used to obtain oxides of barium. These oxides are then heated with aluminium at 1,100ᐤC to form BaAl4. This BaAl4 then reacts with BaO to form Barium metal.
Uses of Barium
Barium is a soft metal which has a wide usage in many fields, the following are some general application and uses of barium.
Barium is often used in the form of alloys such as barium-nickel alloy or barium-aluminium alloy in order to reduce unwanted gases from vacuum tubes. It is also used as a drying agent.
Barium is used in fluorescent lamps as impure barium sulfide glows when exposed to light.
Barium is extensively used by oil and gas industries to make drilling mud which makes it easy to drill through rocks by lubricating the drill.
Barium compounds are used to make various house building and decorating materials such as paints, glass, tiles, bricks and rubber etc.
Barium Nitrate is used in fireworks because it provides the fireworks with a green colour.
Barium oxide is used for coating hot cathode such as in cathode ray tubes that facilitate the release of electrons.
Barium peroxide is used in welding works.
Barium as in barium fluoride is used in optic glasses because of its wide transparency range.
FAQs on Barium
1. What is Barium and what are its main physical properties?
Barium is a chemical element with the symbol Ba and atomic number 56. It is a soft, silvery-white metal belonging to the alkaline earth metals (Group 2) of the periodic table. Key physical properties include:
- It is relatively soft for a metal.
- It is a good conductor of electricity.
- It has a pale yellow shade when pure.
- The melting point of Barium is 730 °C (1,340 °F), and its boiling point is 1900 °C (3450 °F).
2. What are the most common uses of Barium and its compounds?
Barium and its compounds have several important industrial and commercial applications:
- Drilling Fluids: Barium sulfate (in the form of the mineral barite) is widely used to increase the density of drilling mud in oil and gas exploration.
- Medical Imaging: A suspension of barium sulfate, known as a 'barium meal', is used as a radiocontrast agent for X-ray imaging of the digestive system.
- Fireworks: Barium compounds like barium nitrate impart a vibrant green colour to fireworks.
- Electronics: Barium oxide is used to coat the cathodes in fluorescent lamps and cathode-ray tubes to facilitate the release of electrons.
- Other Uses: Barium compounds are also used in the production of paints, bricks, tiles, glass, and rubber.
3. Where is Barium located in the Periodic Table and what does this position indicate?
Barium is located in Group 2 and Period 6 of the Periodic Table. Its position reveals key chemical characteristics:
- As a Group 2 element, it is classified as an alkaline earth metal, sharing properties with elements like calcium and magnesium.
- Its position indicates it has two valence electrons in its outermost shell (the 6s orbital).
- Due to its large atomic size and the ease with which it loses these two electrons, Barium is one of the most reactive elements in its group.
4. Why is Barium metal never found in its pure form in nature?
Barium is never found as a free element in nature because it is highly reactive. As an alkaline earth metal, it readily loses its two valence electrons to form stable compounds. It quickly reacts with common non-metals in the environment, such as oxygen (to form barium oxide) and sulfur. This is why it is almost always found in mineral forms like barite (BaSO₄) and witherite (BaCO₃).
5. Why does Barium typically form a +2 ion (Ba²⁺)?
Barium forms a stable cation with a +2 charge because of its electronic configuration, which is [Xe] 6s². To achieve the highly stable electron configuration of the preceding noble gas, Xenon (Xe), a Barium atom must lose the two electrons from its outermost 6s orbital. Losing these two electrons is energetically much more favourable than gaining six electrons, resulting in the formation of the stable barium ion, Ba²⁺.
6. Barium compounds are often toxic, so how can Barium Sulfate be safely used for medical X-rays?
The safety of using barium sulfate (BaSO₄) for a 'barium meal' in medicine lies in its extreme insolubility. While soluble barium ions (Ba²⁺) are toxic if absorbed by the body, barium sulfate does not dissolve in water or stomach acids. Because it is insoluble, it is not absorbed into the bloodstream and passes through the digestive tract harmlessly. Its high density effectively blocks X-rays, allowing for clear imaging of the gastrointestinal tract.
7. How does the chemical reactivity of Barium compare to other Group 2 elements like Calcium and Magnesium?
The chemical reactivity of alkaline earth metals increases as you go down Group 2 of the periodic table. Therefore, Barium (Ba) is significantly more reactive than Calcium (Ca) and Magnesium (Mg). This trend occurs because the outermost electrons in Barium are further from the nucleus and are better shielded by inner electron shells, making them easier to remove and participate in chemical reactions.
8. What is the source of the green colour in fireworks?
The vibrant green colour seen in many fireworks is produced by barium compounds. When a volatile compound such as barium nitrate (Ba(NO₃)₂) or barium chlorate is heated to the extreme temperatures inside a firework, the barium ions are excited. As they return to their ground state, they release energy in the form of light with a characteristic green wavelength. This principle is a practical application of atomic emission spectra, similar to a flame test.
