Gallium might just be the most remarkable element on the periodic table, stunning scientists and everyone else with its unique features. It is special due to its extraordinarily low melting point of just 29.76∘C (85.57∘F), as this metal can change its state from solid to liquid by just sitting on the palm of a human hand. However, gallium’s appeal extends far beyond its melting point; it is also vital for modern technology, ranging from semiconductors to solar panels. This article outlines the science of gallium’s unusual traits, its commercial uses, and the unique ways it impacts modern industry. Whatever your background is, be it an avid follower of chemistry, or someone thinking about materials science, get ready to know the stunning world of gallium and understand why this metal is considered to be of immense value.
What is Gallium and Where is it Found on the Periodic Table?
Gallium is a soft silvery metal denoted by the symbol Ga and possesses the atomic number 31. It is categorized as a post-transition metal and can be found in Group 13 of the periodic table, as well as aluminum and indium. It has a melting point of about 29.76 °C (85.57 °F), enabling it to melt in one’s hand. Nonetheless, gallium remains solid at room temperature. Gallium is not found in nature in its elemental form; however, it is typically procured as a byproduct of the extraction of aluminum and zinc.
Understanding the Element Gallium
Gallium is exploited in the electronics industry owing to semiconductors, particularly in the fabrication of gallium arsenide (GaAs) and gallium nitride (GaN), both of which utilize the unique properties of gallium metal. These compounds are primary constituents in the manufacturing of light-emitting diodes (LEDs), laser diodes, and transistors of high frequency. The unique melting characteristics of gallium enable it to be used in high-temperature thermometers and low-melting alloys as well as in the non-research context. Besides, other alloys containing gallium aside from the non-research context widen his scope of application to medical imaging and solar cells, marking the innovations of modern industries.
Discovery by Paul-Émile Lecoq de Boisbaudran
Through spectroscopy, a French chemist named Paul-Émile Lecoq de Boisbaudran discovered gallium in 1875. While examining the zinc ore sphalerite, he noted the compound’s distinct violet spectral lines and the zinc ore sphalerite. Lecoq de Boisbaudran was able to confirm the famed “eka-aluminum” named by Dmitri Mendeleev in 1871 because gallium did not exist in the periodic table at the time.
In honor of his country and in a pun on his last name, Lecoq de Boisbaudran named the element gallium after the Latin word for France; Gallia. Changing “gallus” into “gallus” translates into a rooster. Gallium comes in metal form and its atomic mass is about 69.72, while the atomic number is 31. Gallium is unique because of its low melting point of 29.76 degrees Celsius or 85.57 degrees Fahrenheit. In human hands, gallium can begin to liquefy but its boiling point is 2204 degrees Celsius which is 3999 degrees Fahrenheit. Hence, gallium has a remarkable range of states of matter.
The significance of discovering gallium was the verification of Mendeleev’s predictions concerning the periodic table, additionally proving that spectral analysis has value in chemistry. For other fields of science, the newfound metal displayed possibility and sparked interest during isolation and study.
Comparison with Aluminum and Other Metals
Aluminum and gallium share a couple of characteristics due to their allocated group in the periodic table, Group 13. Both elements possess low density, although aluminum’s density is approximately 2.7 g/cm³ while gallium’s density is slightly higher at 5.91 g/cm³. Still, gallium’s unique property of being liquid at near room temperature is due to its melting point of 29.76°C (85.57 °F), which is significantly greater than aluminum’s 660.32°C (1220.58°F).
Concerning chemistry; both metals are known for having some degree of resistance to corrosion due to possessing a protective oxide layer that forms when there is exposure to air. However, gallium behaves differently in aqueous solutions as it can transform into other compounds like gallium nitrate or gallium chloride under specific conditions. Aluminum is preferred because of its industrial usage due to its lower strength-to-weight ratio and greater availability. On the other hand, gallium is considered more useful in modern technology because of its application in electronics such as semiconductors, LEDs, and photovoltaic panels.
Galium proves to be more useful in high-temperature thermometers and as a substrate for GaAs-based electronics than indium and tin. Even though gallium is relatively rare, with an occurrence of about 19 parts per million in Earth’s crust, its unique properties, particularly its ability to alloy with other metals, continue to spur advancements in materials science and electronics.
Why Does Gallium Melt at Such a Low Temperature?
The Science Behind its Low Melting Point
Gallium’s distinctive atomic structure and metallic bonding traits result in its one-of-a-kind melting point of 29.76°C (85.57°F). Relative to other metals, gallium’s atomic framework results in weak metallic bonds, further distinguishing it. It has a distorted orthorhombic crystal structure, meaning pairs of atoms make stronger bonds with one another while leaving the rest of the metallic lattice to interact weakly with the other atoms. These weak bonds can be overcome with minimal fuel, which is why gallium melts at low temperatures.
Moreover, gallium’s electronic configuration compounds this issue. Although three valence electrons surround gallium, only two participate in metallic bonding leaving behind a loosely bound lattice. Research suggests gallium excels at maintaining equilibrium amidst weaker interatomic bonds and stronger forces within its dense solid state, making it an outlier in the world of metals.
Gallium’s unusual electronic activity makes it usable in any range of alloys, metals, and technologies that operate temperature-sensitive devices.
How Gallium is a Metal Yet Different
Gallium is categorized as a metal because it can conduct electricity and heat, and possesses metallic bonds. Still, there are two key differences with other metals. First, gallium’s melting point is relatively low compared to other metals. Gallium melts at around 29.76°C (85.57°F), allowing it to melt in an individual’s hand. Second, like other metals, gallium does not solidify as quickly in temperature drop, allowing it to remain in liquid form over a larger range of temperatures. Because gallium is relatively non-toxic and has a high boiling point, it remains unique amongst the other metals, allowing the use of gallium in specialized applications like semiconductors and liquid metal technologies.
Role of Metallic Bonding in Low Melting
Gallium’s metallic bonds explain the metal’s low melting point. Gallium’s atoms are barely held together in solid form, as opposed to more rigid metals with higher melting points. This results in weaker metallic bonds. Its low melting point can be explained as an effortless transition to liquid when heat is added due to the ease in the level of bonding to its atomic structure.
Can You Melt Gallium in Your Hand?
Exploring the Room Temperature Phenomenon
Unlike other metals, gallium has a strikingly low melting point of about 29.76 °C (85.57 °F)—just above room temperature. This means gallium can melt just by being held in a person’s hand. The average human skin temperature of about 33 °C (91.4 °F) is well above the melting point of gallium.
Gallium’s melting point phenomenon is a byproduct of its metallic structure. Its atoms are all loosely packed and gallium as a metal requires low energy to break its metallic bonds. Furthermore, gallium has a comparatively higher specific heat capacity of about 0.37 J/g·°C which enables it to easily absorb heat while changing to liquid form.
Owing to its properties, gallium has found use in measuring devices in the form of alloys for thermometers or in device-calibrating test tubes. Beyond the realms of its scientific utility, gallium also serves as an effortless educational tool due to its low melting point.
Safety Considerations When Handling Liquid Gallium
When dealing with the risks presented by exposure or misuse of liquid gallium, an appropriate safety approach should be taken. Under normal circumstances, liquid gallium is relatively non-toxic in small quantities and presents little chemical risk. Nevertheless, prolonged contact with skin should be avoided, as gallium liquid metal can diffuse into the dermis, which may result in irritation or minor staining of the skin.
Avoid inhalation of any vapors formed when gallium is heated. Although gallium possesses low vapor pressure and does not easily evaporate, excessive heating may result in the release of dangerous compounds due to contaminates that are present. Always make certain that proper ventilation is available, or work under a fume hood when heating gallium.
Manage gallium’s already existent interactions with other metals. For example, when in contact with aluminum, gallium may diffuse into aluminum’s structure; this degrades the material’s integrity because gallium disrupts the crystalline lattice of aluminum. There is a possibility of serious structural failure in certain environments. Store gallium in glass or plastic since these materials are non-reactive and may be safely used with gallium.
It is necessary to mention that even though gallium is not typically deemed a hazardous material, it still requires a specific disposal approach to mitigate potential environmental effects. Gallium that has been used, or gallium that has been mixed with other materials, should not be thrown away in regular waste containers. It needs to be treated in a hazardous waste disposal facility or a dedicated recycling center.
Ultimately, the scientific norm dictates precautions should be taken to avoid unshielded exposure and opt for protective gloves and goggles when dealing with liquid gallium. These actions support the maintenance of proper safety levels on the eyes and skin. Keeping gallium in a tightly closed container at a constant room temperature eliminates the possibility of spillage or contamination during operational phases.
What are the Chemical Properties and Oxidation States of Gallium?
Reactivity and Oxidation States of Gallium
This element is reactive, especially at higher temperatures, showing notable oxidation states of +1 and +3. The +3 oxidation state is most commonly found and is more stable in gallium compounds such as gallium(III) oxide (Ga₂O₃) or gallium chloride (GaCl₃). The +1 state, although less stable, may be found in certain compounds such as gallium(I) chloride (GaCl).
Gallium is easily reactive with acids and alkalis, exhibiting its amphoteric nature. For example, it dissolves in hydrochloric acid to form gallium chloride, while sodium hydroxide will yield gallate ions (GaO₂⁻). Gallium also reacts with oxygen to form gallium oxide. This compound is useful in the manufacturing of optoelectronic devices due to its wide bandgap and semiconductor properties.
Data shows that gallium has low ionization energies when compared to neighboring elements of the periodic table. This aids the reactivity needed to bond with other elements. With a melting point of approximately 29.76°C, gallium can exist as a liquid near room temperature. This is useful for many industries like electronics or high-temperature thermometers which use liquid metals. These traits and states increase galliums appeal for materials in modern technology as well as materials science.
Interaction with Water and Hydrogen
The interaction of gallium with water and hydrogen is unique. At room temperature, gallium does not dissolve in water, but at higher temperatures, steam can oxidize gallium to gallium (III) oxide (Ga₂O₃) while hydrogen is liberated. This oxidation reaction exemplifies the redox activity of gallium that is possible at certain temperatures. For example this can be written as:
2Ga + 3H₂O → Ga₂O₃ + 3H₂
Also, this reaction has a good significance because gallium as a catalyst in hydrogen generation research is far more useful than expected due to its properties when combined with aluminum. When aluminum-gallium alloys are put in water, a comparable reaction takes place that generates hydrogen gas at a very fast rate with no CO2 emissions. This research is aimed at developing environmentally benign sources of hydrogen fuel to be used in renewable energy systems.
Gallium was also found to be beneficial for hydrogen storage by some researchers. Its alloying with some metals, such as aluminum, possesses a low melting point which increases the possibility of designing reusable hydrogen-release storage systems. Recent studies in this field have indicated that materials containing gallium could form stable structures for efficient hydrogen storage and production, thus contributing to clean energy initiatives.
The previously mentioned interactions demonstrate the relevance of gallium in the advancement of hydrogen technologies, including hydrogen fuel cells, clean energy production, and materials engineering.
Use in Semiconductor Technologies
Semiconductors owe their gallium arsenide (GaAs) and gallium nitride (GaN) compounds to gallium’s crucial role. These elements are utilized in high-speed electronics, power devices, and optoelectronics due to their superior thermal properties and electron mobility. GaN is the key material used in energy-efficient LEDs and 5G communication systems as well as power transistors. In addition, gallium-based semiconductors play a vital role in the manufacturing of solar cells improving their efficiency in transforming sunlight into electricity. All these properties showcase gallium’s importance in developing new electronic technologies and energy technologies.
How is Gallium Used in Alloys and Other Applications?
Common Gallium Alloys and Their Uses
Gallium is utilized in alloys to achieve low melting points or increased strength. One of the most famous is the Gallium-Indium-Tin Alloy (Galinstan), a liquid at room temperature that can be used in thermometers, cooling systems, and robotics. Aluminum gallium alloys are also used to produce hydrogen through a reaction with water. These alloys take advantage of gallium’s unique property of remaining a stable liquid or increasing efficiency. This makes them useful for industrial and scientific purposes.
Role in High-Temperature Thermometers
The significance of gallium lies in its melting range as a liquid and termeropmeric alloy since its boiling point is very high at 2204 degrees Celsius (4000 degrees Fahrenheit). Its usage as a component of alloys such as Galinstan makes it easier to substitute mercury because it is not poisonous and is safer for the environment. These thermometers can be used in industries such as metallurgy, aerospace engineering, and other fields that require knowledge of physical science because of the high degrees of accuracy that are reversible to changes in force and movement even in extreme situations.
Application in Gallium Arsenide and Gallium Nitride
The most notable compounds of gallium used in the production of modern electronics and optoelectronics technology include Gallium Arsenide (GaAs) and Gallium Nitride (GaN).
- Semiconductor Industry: The capacity of GaAs to be employed in high-speed electronics (for example, in mobile phones) as one of the most widely used materials stems from its superior mobility of electrons in comparison to silicon. Its exceptional properties result in faster signal processing in devices such as high-frequency integrated circuits and microwave transistors.
- Solar Cells: GaAs is often used in high-efficiency photovoltaic cells, especially in space applications, where its ability to withstand radiation and high temperatures outperforms silicon-based cells, highlighting the significance of the existence of gallium.
- Light-Emitting Diodes (LEDs) and Infrared Lasers: This crucial element for optoelectronics can be grown with great precision and astounding material properties, this enables GaAs to serve as an efficient supplier for LEDs and laser diodes operating in infrared wavelengths.
Data Point Example:
- The performance of a GaAs based electronic component is remarkable. The mobility of electrons ranges from approximately 8,500 cm²/V·s at 300K which is 5.6 times higher than that of silicon whose performance is only 1500 cm²/V·s.
- Its efficiency in lab conditions can exceed 30% making GaAs-based solar cells a prime alternative in energy-critical platforms.
Gallium Nitride:
- Power Electronics: GaN is distinguished with high thermal stability and efficiency together with high breakdown voltage. It serves as a preferable material for power transistors and amplifiers operating in extreme environments such as electric vehicles, renewable energy systems, and satellite systems.
- Led Technology: GaN devises the basis for blue and white LED production, powering energy-efficient solid-state lighting systems.
- 5G Communication and Radar Technology: Its high-frequency operational capabilities render GaN essential to contemporary telecommunications and defense technologies.
Data Point Examples:
- The breakdown electric field of GaN surpasses 3 MV/cm in comparison to silicon’s 0.3 MV/cm. This enables devices to be smaller, more efficient, and powerful.
- GaN-based power transistors can operate at frequencies exceeding 30 GHz. This is advantageous for wireless networks of the future.
The versatility and importance of gallium compounds in driving industry innovations from renewable energy to advanced communication systems are illustrated through both GaAs and GaN. Their unique properties aid in addressing the global demands for efficiency and miniaturization by revolutionizing the performance of electronic and photonic devices.
Frequently Asked Questions (FAQs)
Q: Is it correct that gallium can melt in one’s hand?
A: Yes, it is correct. Gallium is a metal that is said to exist in a liquid state at room temperature. Solid gallium will transition its state to a liquid if heat is supplied and in this case, the temperature of gallium’s melting point is 85.6 Fahrenheit or 29.8 degrees Celsius. Since the temperature is slightly above room temperature, the heat from the hand can melt gallium.
Q: What is gallium’s symbol and atomic number?
A. Ga which represents gallium has atomic number 31. In 1875, French chemist Paul-Émile Lecoq de Boisbaudran discovered it using spectroscopy techniques.
Q: How does gallium’s melting point compare to its boiling point?
A. Gallium has one of the highest boiling points at 3999 Fahrenheit or 2204 degrees Celsius while having a very low melting point at 85.6 Fahrenheit or 29.8 degrees Celsius. The difference in temperatures allows gallium to be in a liquid state therefore making gallium the only element having the highest liquid range.
Q: What was the prediction made to discover gallium and which scientist made the prediction?
A: In 1875, gallium was discovered by French chemist Paul-Émile Lecoq de Boisbaudran. But his prediction was anticipated earlier by Russian chemist Dmitri Mendeleev who noticed the gap in the periodically arranged table of elements and called it ‘eka-aluminum’.
Q: What are some common uses for gallium?
A: Gallium has many uses, including in semiconductors, LEDs, solar panels, and high-temperature thermometers. Gallium compounds like gallium arsenide and gallium nitride have special significance in the electronics industry.
Q: How does gallium compare to other metals like aluminum?
A: In several aspects such as appearance and forming a protective oxide layer, gallium is identical to aluminum. However, gallium is much softer and has a lower melting point. While aluminum is a solid at room temperature, gallium is a liquid under some conditions at room temperature.
Q: Is it safe to touch gallium?
A: Contacts with gallium are certainly short, and very safe to make unnecessary, as elemental gallium is non-toxic. Stains, however, are real and can come from long exposures. Some gallium compounds are ugly and should be avoided.
Q: What alloys with gallium?
A: Willing to bind with aluminum, gallium will also bond with a great number of other types of metals. The good of making bonds is pretty balanced with the bad of making bonds brittle. There are several uses of gallium and compounds.
Q: Is it possible to locate gallium in nature?
A: No, gallium cannot be easily found as it does not exist in an element state. Processing zinc and bauxite ore will yield gallium as a byproduct, but other minerals require purification post-extraction for the gallium atom.
Reference Sources
1. T-T90 Measurements With Acoustic Gas Thermometers to Gallium Melting Point in Neon Gas
- Authors: J. Widiatmo et al.
- Publication Year: 2024
- Source: AIP Conference Proceedings
- Summary: This research attempts the measurement of T-T90 steps with the gas thermometers up to the gallium melting point. The work tries to impose new bounds in the temperature measurement concerning thermodynamic standards. The approach utilized in neon is significant for the establishment of dependable temperature references in measurement science and industry.
- Key Findings: The findings improve the accuracy levels of temperature measurements at the gallium melting point which is important in several areas of metrology and materials science(Widiatmo et al., 2024).
2. From the Melting Point of Gallium to the Mercury Triple Point: A Study on Thermodynamic Temperature Measurement
- Authors: J. Widiatmo et al.
- Publication Date: 2024-07-01
- Source: International Journal of Thermophysics
- Summary: This paper details the series of measurement procedures conducted to thermodynamically quantify temperatures from the gallium melting point to the mercury triple point. The work is remarkable because it underlines the relevance and impact of temperature accuracy in scientific and industrial domains.
- Key Findings: As part of the research, the author has documented the methods employed to measure temperatures between several fixed reference points which enhanced the understanding of thermodynamic properties and standards(Widiatmo et al., 2024).
3. New Realization of the Gallium Melting Point at NIM and Validation Through Comparison with PTB
- Authors: Xiaoke Yan and others
- Publication Year: 2024
- Source: AIP Conference Proceedings Press
- Summary: The study describes the new effort at NIM concerning the realization of the gallium melting point and its validation by measurement against PTB’s realization. This attempt is made to provide a more precise and consistent standard for the melting point of gallium.
- Key Findings: The conclusion asserts that the certainty of the new realization is consistent with other recognized international standards, thereby strengthening the reliability of the gallium melting point as a thermometric fixed point (Yan et al., 2024).
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