What is Gallium? Properties, Common Uses, and Interesting Facts
Gallium is essential in chemistry and helps students understand various practical and theoretical applications related to this topic.
What is Gallium in Chemistry?
A gallium refers to a soft, silvery metal with atomic number 31, belonging to group 13 of the periodic table. This concept appears in chapters related to elements, periodic trends, and semiconductor materials, making it a foundational part of your chemistry syllabus.
Gallium is best known for its low melting point—just above room temperature—and its wide use in electronics like LEDs and semiconductors.
Molecular Formula and Composition
The molecular formula of gallium as an element is simply "Ga." It consists of only gallium atoms and is categorized under the class of post-transition metals from group 13.
In its compounds, such as gallium arsenide (GaAs) and gallium nitride (GaN), it combines with other elements to offer valuable semiconductor behavior. Gallium has an atomic mass of 69.72 g/mol, and it often features in chemistry classes when discussing the physical and atomic properties of elements.
Preparation and Synthesis Methods
Gallium is not found free in nature. Instead, it is extracted mainly as a by-product during the refining of aluminum (from bauxite) and zinc ores. Industrially, gallium is separated by electrolysis or chemical displacement from the solutions left after these ores are processed.
Laboratory preparation involves passing an electric current through gallium compounds or smelting gallium-containing minerals. This practical knowledge ties into the extraction of metals unit in your syllabus.
Physical Properties of Gallium
Gallium has several unusual physical properties that make it a topic of curiosity:
- Melting point: about 29.8°C (can melt in your hand)
- Boiling point: 2204°C (very high compared to its melting point)
- Density: 5.91 g/cm³
- Appearance: Silvery, shiny, and soft—can be cut with a knife
- State: Solid at room temperature, but melts slightly above it
- Solubility: Stable in water and air, not highly reactive
- Odor: Odorless
Chemical Properties and Reactions
Gallium is not as reactive as alkali metals but can form several useful compounds:
- Forms gallium(III) oxide when heated with oxygen
- Reacts with both acids and alkalis, showing amphoteric behavior
- Can diffuse into other metals like aluminum and gold, making them brittle
- Forms important semiconducting compounds such as gallium arsenide (GaAs) and gallium nitride (GaN)
Frequent Related Errors
- Confusing gallium with other liquid metals like mercury (Ga is less toxic and less reactive)
- Assuming gallium is dangerous to touch—it's not toxic, but can slightly stain skin
- Mixing up the group number or period in the periodic table—gallium is in group 13
- Forgetting its solid-liquid transition near room temperature for exam questions
Uses of Gallium in Real Life
Gallium is widely used in several high-tech and everyday applications:
- Manufacture of semiconductors, especially gallium arsenide (GaAs) chips for electronics
- Production of LEDs and laser diodes
- Special glass mirrors and thermometers as a safe alternative to mercury
- Medical imaging and radiopharmaceuticals (e.g., gallium-67 scans)
- Alloys—gallium forms low-melting alloys used in temperature-sensitive devices
Step-by-Step Reaction Example
- Prepare a strip of aluminum and place a drop of liquid gallium on its surface.
Gallium diffuses into the grain boundaries of aluminum, weakening it. - Observe the aluminum structure after a few hours.
The aluminum becomes brittle and can be easily broken apart—the basis for a famous chemistry demonstration.
Lab or Experimental Tips
Remember gallium by the rule: "Melts in your hand—boils at a blast furnace." Vedantu educators often use this tip in live sessions to help students recall its unusual melting and boiling points for quick exam reference.
Try This Yourself
- Write the electron configuration of gallium.
- List two real-life uses of gallium compounds.
- Explain why gallium is safer than mercury for use in thermometers.
Final Wrap-Up
We explored gallium—its structure, properties, reactions, and real-life importance. For more in-depth explanations and exam-prep tips, explore live classes and notes on Vedantu.
FAQs on Gallium – Properties, Uses, and Key Information for Students
1. What is gallium and where is it found in the periodic table?
Gallium is a soft, silvery metal with the chemical symbol Ga and atomic number 31, found in group 13 of the periodic table. It is categorized as a post-transition metal and is not found in its pure form in nature, but is extracted from ores like bauxite and zinc ores.
2. What are the main physical properties of gallium?
Gallium has several unique physical properties including:
- Melting point: 29.8°C (can melt in your hand)
- Boiling point: 2204°C
- Appearance: Soft, silvery metal
- Density: 5.91 g/cm³ at room temperature
- It remains a liquid over a wide temperature range, which is unusual for metals.
3. What are the key uses of gallium?
Gallium is used in various industries and products, such as:
- Semiconductors: Gallium arsenide (GaAs) and gallium nitride (GaN) in LEDs, lasers, and solar cells
- Medical imaging: As a radiotracer in gallium scans
- Alloys: Used in low-melting fusible alloys
- Thermometers: As a non-toxic alternative to mercury
4. Is gallium safe to handle and use?
Gallium is generally considered safe to handle in small amounts. It is not highly toxic to humans but can stain the skin. However, prolonged exposure should be avoided, and hands should be washed after handling. Gallium compounds may be more hazardous and require careful handling.
5. Why does gallium melt in your hand?
Gallium melts in your hand because its melting point is 29.8°C, which is just below average human body temperature. It absorbs heat from your hand and transitions from solid to liquid.
6. How does gallium react with other metals such as aluminum?
Gallium reacts with aluminum by diffusing into its crystal structure, weakening the metal and making it brittle. This reaction can damage aluminum objects and is often used as a demonstration in chemistry classes.
7. What are the most important gallium compounds?
The most significant gallium compounds include:
- Gallium arsenide (GaAs): Used in electronic devices, LEDs, and solar panels
- Gallium nitride (GaN): Used in high-power electronics and blue LEDs
- Gallium(III) oxide (Ga2O3): Used in research and as a semiconductor material
8. Is gallium expensive and why?
Gallium is considered a rare and moderately expensive metal. Its price varies due to its limited availability (mainly as a byproduct of aluminum and zinc production) and high demand for electronic components.
9. Who discovered gallium and how?
Gallium was discovered by French chemist Paul-Émile Lecoq de Boisbaudran in 1875. He identified it through its spectral lines while analyzing zinc blende and later isolated it using electrolysis. Gallium’s name comes from ‘Gallia,’ the Latin name for France.
10. Can gallium be used for jewelry or coins?
Gallium is not practical for use in jewelry or coins due to its soft nature and low melting point. It would easily deform or melt with the heat from your hand.
11. How is gallium extracted from its ores?
Gallium is obtained as a byproduct during the extraction of aluminum and zinc. The extraction steps typically include:
- Leaching and purification of gallium ions
- Electrolytic deposition to create pure gallium metal
12. Does gallium pose any environmental risks?
Gallium metal is not highly toxic and poses low environmental risk. However, certain gallium compounds should be handled carefully and disposed of properly to avoid environmental contamination, as recommended by safety guidelines.
