Gallium

Gallium, with the atomic number 31, is a chemical element that appears as a blue-grey metal with an orthorhombic crystalline structure in its solid form. Pure Gallium, however, has a striking silvery appearance. It does not occur naturally in its pure form and is not typically extracted from its compounds as a primary source.

1.0Introduction

Gallium, predicted by Mendeleev in 1871 and initially named eka-aluminium, was discovered and isolated by Paul-Émile Lecoq de Boisbaudran in 1875. He called it after Gallia, the Latin word for France. The isolation of Gallium involved recognizing unexpected spectral lines in sphalerite, a zinc mineral, which led to its extraction and characterization.

Initially obscure, Gallium gained commercial significance in the 1970s by developing gallium arsenide LEDs and laser diodes. Gallium is as soft as lead at room temperature and can be cut with a knife. It has a notably low melting point and can even begin to melt in a warm hand. Uniquely, unlike most metals, Gallium expands upon freezing.

2.0Physical Properties of Gallium

• Appearance: Soft, shiny metal with a silver-blue colour.
• Natural Occurrence: This does not occur in pure form naturally; it must be extracted through smelting.
• Melting Point: Approximately 29°C; can melt in your hand.
• State at Room Temperature: Liquid is one of the few elements (along with mercury, rubidium, and caesium) that are liquid at room temperature.
• Adhesion: Adheres well to glass and porcelain.
• Supercooling: Can remain liquid below its melting point without solidifying.
• Alloying: Forms alloys with metals like aluminium and zinc; notable alloys include Galinstan (Gallium, tin, and indium).
• Boiling Point: Approximately 2200°C.
• Density: 5.907 g/cm³.
• Unique Property: Has a large ratio between melting and boiling points.

3.0Chemical properties of Gallium

Gallium is a fascinating element with several distinctive chemical properties. These properties make gallium valuable for a wide range of applications, from semiconductor technology to high-temperature thermometers.

• Reactivity with Air: Gallium remains stable in air at room temperature due to the formation of a protective oxide layer. However, when heated to approximately 500°C, it reacts with oxygen to produce gallium(III) oxide (Ga₂O₃).
• Reaction with Acids: Gallium readily dissolves in both dilute and concentrated acids. For instance, its reaction with hydrochloric acid (HCl) produces gallium chloride (GaCl₃) and hydrogen gas.
• Reaction with Alkalis: Gallium also dissolves in strong alkalis like sodium hydroxide (NaOH), forming gallate ions (GaO₂⁻) and releasing hydrogen gas.
• Amphoteric Nature: Gallium's amphoteric behavior allows it to react with both acids and bases, making it a versatile element in chemical reactions.
• Compound Formation: Gallium forms a variety of compounds, including gallium trichloride (GaCl₃), gallium(III) oxide (Ga₂O₃), and gallium nitride (GaN). Gallium nitride, in particular, is crucial in the production of LEDs and semiconductor devices.
• Alloy Formation: Gallium readily forms alloys with many metals, some of which are liquid at room temperature. One such alloy is the gallium-indium-tin alloy, and has applications in various fields . .
• Low Melting Point: With a melting point of just 29.76°C (85.57°F), gallium can melt in the palm of your hand, a characteristic that is rare among metals and contributes to its uniqueness.

4.0Uses Of Gallium

Semiconductor Industry:

• It is extensively used in the production of integrated circuits and electronic chips.
• Gallium compounds are essential in laser devices and widely used in manufacturing LEDs.

Medical Thermometers:

• Gallium, a liquid metal at room temperature, is a non-toxic alternative to mercury in medical thermometers.

Alloy Formation:

• Easily forms alloys with other metals, substituting toxic mercury alloys in various applications.

Mirror Production:

• Gallium wets and adheres to glass, making it valuable in producing high-quality mirrors.

Nuclear Industry:

• Gallium alloy is used to stabilize plutonium in nuclear devices.

Cooling Systems:

• Due to their excellent thermal conductivity, gallium alloys are used in cooling systems for machines and electronic devices, such as computers.

Biomedical Applications:

• Widely used in the biomedical field, with several gallium salts employed in medical treatments.
• Some gallium compounds have demonstrated anti-cancer properties.
• Ongoing research is exploring gallium's potential in treating inflammation, cancer, and other diseases.