Tin Metal: Definition, Composition, Properties, and Applications
Tin is a chemical element with the symbol Sn and atomic number 50 on the periodic table. It is a silver-white, malleable, and relatively soft metal. Tin ore is typically found in nature in the form of minerals like cassiterite (tin dioxide), which is the primary source of commercially mined tin. It has a relatively low melting point for a metal (about 232 °C or 449.6 °F) and a density of approximately 7.31 g/cm³. Tin is malleable, so it can be rolled into thin sheets and drawn into wires.
Tin is particularly valuable as an alloying element when combined with other metals. Alloys that contain tin include: bronze, babbitt metal, pewter, and various solders. Tin compounds are used to produce various chemicals, such as organotin compounds, which are employed as stabilizers and catalysts.
This article will discuss tin metal, its composition, properties, and applications.
What Is Tin?
Tin is an elemental metal, meaning it is composed of only one type of atom and cannot be broken down into simpler substances. Tin atoms have 50 protons and typically around 69 neutrons, giving the most abundant isotope (¹¹⁹Sn) a mass number of 119.
What Is the Other Term for Tin Metal?
Another common term for tin is its Latin name, stannum. While tin is the more widely recognized name for the element, stannum is sometimes used in historical or scientific contexts, and it's the origin of the periodic table symbol, Sn.
What Is the Origin of Tin?
Tin is formed through nucleosynthesis during supernova explosions, like all elements with atomic numbers greater than iron (26). It is considered a siderophile element, meaning it has an affinity for iron and is often found in association with iron-containing minerals.
Most of the tin used today has been present in the Earth’s crust since its early formation. Tin ores such as cassiterite (SnO₂) are typically found in granitic rocks, pegmatites, and hydrothermal vein systems, where geologic fluid movements have concentrated the minerals over time.
Humans have been extracting tin for over 5,000 years. Due to its relatively low melting point and ease of extraction, tin was one of the earliest metals used in metallurgy, particularly in the production of bronze.
What Is Tin Made Of?
As an elemental metal, pure tin is composed only of tin atoms. It belongs to Group 14 of the periodic table and has an atomic number of 50, meaning each atom contains 50 protons. Tin has 10 stable isotopes—more than any other element—which vary in neutron number from 62 to 74.
How Is Tin Metal Made?
Tin metal is produced through mining and refining. The primary source is cassiterite (SnO₂), mined from underground and open-pit deposits. After extraction, the ore is crushed and ground, and tin is concentrated using gravity separation methods. The concentrated ore is then smelted in a furnace with carbon (typically coal or charcoal), which reduces tin oxide to metallic tin and releases CO₂. The crude tin is further refined by temperature-controlled liquation or electrolytic refining to remove impurities such as copper and iron. The final product is cast into ingots, bars, or other usable forms.
The concentrated tin ore is heated in a furnace with carbon (often in the form of coal or charcoal). This process reduces the tin oxide in cassiterite to produce tin metal and carbon dioxide gas, as the carbon preferentially oxidizes and leaves the tin as a pure metal. The resulting crude “tin” metal will contain impurities like iron, copper, and other metals. The next step refines the metal to remove these impurities. It’s most often done through temperature-controlled liquation, in which the metal is heated to liquefy the tin content but leaves the other elements as solids that can be separated.
Electrolytic refining is often employed for additional purification. In this process, impure tin is dissolved in an electrolyte solution, and a direct current is passed through it. Tin ions migrate to the cathode, forming pure tin metal without any non-metallic contaminants. Other metals are removed by careful electrode voltage and current control. The resulting high-purity tin is cast into various forms — ingots, bars, or sheets, depending on its intended use.
What Is the Color of Tin?
Tin in its unoxidized state has a lustrous, silver appearance. It reflects light with near mirror-like precision when polished.
What Does Tin Look Like?
Tin appears silver and shiny when freshly cut or polished. Upon exposure to air, it gradually oxidizes, developing a gray or powdery-white surface layer.
What Are the Chemical Properties of Tin?
Table 1 below shows the chemical properties of tin:
| Property | Description |
|---|---|
Property Atomic Number | Description 50 |
Property Atomic Mass | Description 118.71 u |
Property Electron Configuration | Description [Kr] 4d^10 5s^2 5p^2 |
Property Oxidation States | Description +2, +4 |
Property Electronegativity | Description 1.96 (Pauling scale) |
Property Solubility | Description Insoluble in water; reacts with concentrated acids to form soluble compounds. |
Property Reactivity | Description Relatively unreactive in air and water at room temperature |
Property Corrosion Resistance | Description Resistant to corrosion in many environments |
Property Common Compounds | Description Forms various tin compounds, including oxides and salts |
Property Isotopes | Description Tin has 10 stable isotopes; Sn-120 is the most abundant |
| Property | Description |
|---|---|
Property Phase at Room Temp. | Description Solid |
Property Color | Description Silvery-white |
Property Density | Description 7.31 g/cm³ |
Property Melting Point | Description 231.9 °C |
Property Boiling Point | Description 2,270 °C |
Property Hardness (Mohs) | Description 1.5 |
Property Malleability | Description Highly malleable, can be rolled into thin sheets |
Property Ductility | Description Ductile, can be drawn into thin wires |
Property Crystal Structure | Description Tetragonal (white tin) |
Property Electrical Conductivity | Description Good electrical conductivity |
Property Thermal Conductivity | Description Good thermal conductivity (~67 W/m·K at 300 K) |
Property Magnetic Properties | Description Diamagnetic (non-magnetic under normal conditions) |
Property Sound Transmission | Description Good sound transmission; sometimes used in organ pipes for tonal quality |
Property Tin Pest | Description Subject to "tin pest" at low temperatures (below about -13.2 °C) |
Is Tin One of the Hardest Metals on Earth?
No, tin is a relatively soft and malleable metal with low tensile strength and a Mohs hardness of approximately 1.5. It is far from being one of the hardest metals.
Can You Laser Cut Tin?
Yes, tin can be laser cut, especially in thin sheets and low-power applications. However, its low melting point (231.93 °C) means it can melt or deform easily, so precise control of laser parameters is required. It is also suitable for laser engraving.
Is Tin Magnetic?
No, tin is not magnetic in either of its allotropes. Both white tin (β-tin), which is stable above -13.2 °C, and gray tin (α-tin), which forms below this temperature, are diamagnetic. This means they are weakly repelled by magnetic fields and do not retain magnetization.
What Are the Applications of Tin?
Tin is used in various industries due to its unique properties. Some of these applications are discussed below:
1. Solder
Tin is the primary component in most types of solder. Tin and other low-melting-point alloys are important in electronics, cosmetic and structural jointing in plumbing, jewelry, etc. In solder, tin is alloyed with several metals — lead, silver, copper, antimony, zinc, and more. These create specialist materials that can bond or join a huge range of metal components and conduct electricity.
Tin’s low melting point makes it suitable for precise and controlled soldering applications in electronics assembly and plumbing connections. Its ability to form strong, reliable, and electrically conductive bonds between components has made it indispensable in the manufacture and repair of electronic devices. It goes into everything from consumer gadgets to aerospace equipment. Tin-silver alloys are widely used in high-value and decorative applications.
2. Optoelectronics
Tin plays an important role in optoelectronics, especially in the form of compounds like tin dioxide (SnO₂) used in transparent conductive films and gas sensors. One notable application is in thin tin dioxide (SnO2) films, which are used in gas sensors for detecting pollutants and toxic gases. The capacitive or conductive properties of the films vary according to the specific alloying chemistry.
Tin-based perovskite materials have also gained attention for use in solar cells and LEDs due to their tunable optoelectronic properties. These structures can be adjusted to enhance device performance. Tin’s unique properties, including its electrical conductivity and willingness to alloy with other metals, make it a valuable element in the development of cutting-edge optoelectronic technologies for energy conversion, sensing, and display applications.
3. Tin Plating
Tin plating, or tinning, is a surface finishing process that applies a thin layer of tin onto a substrate such as copper or steel. It can be done to improve corrosion resistance (preventing the underlying metal from rusting or oxidizing), enhance solderability (making it easier to join components through soldering), or improve aesthetics.
Tin plating is common in electronic components, food and beverage cans, and various industrial applications that need to resist corrosion or improve solderability.
4. Glass Production
Tin compounds, particularly tin dioxide (SnO2), play a significant role in the glass industry. Tin dioxide (SnO₂) is used as a transparent conductive oxide (TCO) coating on low-emissivity (low-E) glass for energy-efficient windows. Low-E glass is designed to minimize heat transfer through windows, improving energy efficiency in buildings. This enhanced ability to reflect heat while allowing visible light to pass through can make buildings more energy-efficient and environmentally friendly. Tin compounds are essential for modern glass coatings used in architectural and automotive applications.
5. Dental Applications
Tin is used in various dental applications due to its biocompatibility and safety for use in the oral cavity. One common application is in dental amalgams, where tin is alloyed with mercury, silver, and copper to form a durable filling material. Dental amalgams have been used for over a century because they’re durable and cost-effective, though they’re now often overshadowed by harder wearing and more robust polymer and ceramic solutions.
Tin-based compounds, such as stannous fluoride, are also used in toothpaste and mouthwash to prevent tooth decay and reduce sensitivity. They strengthen tooth enamel and have antibacterial properties.
6. Specialized Alloys
Some specialized alloys incorporate tin in varying amounts alongside other metals. It’s done to give the alloy specific properties.
Bronze is one of the oldest tin-based alloys, typically made from copper and tin, sometimes with added nickel or aluminum to improve corrosion resistance and strength. Bronzes are known for strength, corrosion resistance, and ease of working. Bronze is widely used in bearings (alloyed with phosphor), marine equipment, water processing equipment, and decorative items.
Pewter is a tin-based alloy with small amounts of copper, antimony, and sometimes other metals. It is known for its low melting point and malleability. It used to be very common in decorative items, utensils, and tableware, though its use is declining.
Babbitt metals are tin-based bearing alloys containing antimony and copper, known for their low friction and conformability. They’re used as plane-bearing surfacing materials due to their low friction, excellent conformability, self-healing properties, and load-bearing capacity. White metals are similar alloys that are often used interchangeably with babbitt metals.
Many other tin-centric formulations are alloyed with lead (e.g., Sn-Pb solder), silver, or other metals. These alloys have different melting points to suit various applications and are used to join components in electronics, plumbing, and metalwork, or for preparing surfaces for soldering by pre-coating (tinning) for low oxidation and solder affinity.
How Is Tin Metal Used in TIG Welding?
Tin has a low melting point and is not used in TIG welding, which requires metals capable of withstanding high temperatures and forming strong welds.
What Are the Advantages of Tin?
Tin offers several advantages that make it valuable in various applications:
- The excellent corrosion resistance makes it suitable for use in environments that would cause rust or corrosion in other metals. Though its oxide coating is not oxygen-proof, its corrosion rate is low in mild conditions.
- Tin lends its malleability to many alloys. It can be easily shaped, rolled, or drawn into thin sheets or wires, allowing it to be used in various forms and applications.
- Pure tin exhibits a low melting point (231.9 °C) and imparts this property to many of the alloys it forms.
- Because it’s biocompatible, tin is safe for dental applications, food packaging, and medical devices.
- Tin conducts electricity, so it’s used in electrical and electronic components, including solders and coatings. While less conductive than copper or silver, it is effective over short distances in joint materials.
- It is readily miscible in alloys with various other metals, enhancing their properties. Bronze, babbitt metal, and pewter are examples of such alloys.
- Tin dioxide (SnO2) is used as a transparent conducting oxide (TCO) in devices like solar panels, touchscreens, and low-emissivity (low-E) glass.
- Tin compounds have a wide spectrum of industrial applications, including as catalysts, stabilizers, and pigments in paints.
- Tin's use in products like low-E glass can contribute to improved energy efficiency in buildings.
What Are the Disadvantages of Tin?
Listed below are the disadvantages of tin:
- It has very low tensile and shear strength compared to many other metals, making it entirely unsuitable for bulk structural applications.
- At low temperatures (below −13.2 °C), tin transforms from the metallic β-phase to the brittle α-phase — a phenomenon known as “tin pest” — which can cause disintegration in affected components.
- Tin's low melting point makes it unsuitable for high-temperature applications.
- While not a precious metal, tin can be relatively costly compared to many industrial alloys.
- While tin is generally corrosion resistant, it may corrode in some aggressive environments, particularly if exposed to strong acids and alkalis.
- While tin is a good conductor of electricity, it is not as conductive as some other metals like copper or silver, so it cannot serve as a long-path conductor.
- Tin oxidizes more rapidly at high temperatures, forming tin oxides that can degrade electrical or mechanical performance in certain applications.
Is Tin a Cheap Metal?
No. Tin is not typically considered a cheap metal. While it is not as expensive or rare as precious metals, it is more expensive than abundant metals like iron, aluminum, or copper.
Is Tin Worth More Than Gold?
No. As of 2025, tin has a typical spot price of around $25–30 per kilogram, whereas gold can exceed $70,000 per kilogram.
Is Tin a Rare Metal?
No. Tin is not considered a rare metal in the Earth's crust, with an abundance of about two parts per million (ppm), placing it among moderately abundant elements. However, economically viable tin deposits (primarily cassiterite) are geographically limited, and their availability can be influenced by geological and geopolitical factors.
Does Tin Rust?
Not exactly. Tin does not “rust” in the traditional sense, as rust refers specifically to iron oxide. However, tin can corrode under certain conditions. It resists corrosion in dry air at room temperature due to a protective oxide film, but is more susceptible to corrosion in moist, acidic, or alkaline environments, or at elevated temperatures.
What Is the Difference Between Tin Metal and Tin Bronze?
Tin and bronze are distinct materials with different compositions, properties, and applications. Pure tin has low mechanical strength and is used mainly for coatings or alloying. Bronze is a high-strength alloy of copper and tin, combining toughness and corrosion resistance. Tin lowers the melting point of copper, making bronze easier to cast, and also improves its ductility and wear resistance.
Summary
This article presented tin metal, explained its composition and characteristics, and discussed its various properties and applications.
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