Platinum

Introduction

Platinum is a precious metal that holds significant value and is known for its distinctive properties. It is a dense, malleable, and ductile metal with a lustrous silver-white appearance. Platinum belongs to the platinum group metals (PGMs), which also include palladium, rhodium, ruthenium, iridium, and osmium.

Platinum has a long history of human use and has been highly regarded for its rarity and beauty. Its name originates from the Spanish word “platina,” meaning “little silver,” reflecting its resemblance to silver. Platinum has a high melting point and exceptional resistance to corrosion, making it highly desirable in various industrial applications.

One of the primary uses of platinum is in the production of catalytic converters, where it helps to reduce harmful emissions from vehicles by converting toxic gases into less harmful substances. It is also extensively used in the chemical industry, in the field of jewelry, technological applications and in the medical field

The scarcity and versatility of platinum make it a highly sought-after metal in both industrial and consumer sectors. Its unique combination of physical and chemical properties, coupled with its aesthetic appeal, contribute to its enduring popularity and significance in numerous fields.

Physical Properties of Platinum

1. Appearance: Platinum has a lustrous silver-white color, often described as a bright metallic gray. It has a highly reflective surface, lending it a distinct and attractive appearance.
2. Density: Platinum is a dense metal, with a density of approximately 21.45 grams per cubic centimeter (g/cm³). Its high density contributes to its weight and heftiness.
3. Malleability: Platinum is highly malleable, meaning it can be easily hammered, rolled, or shaped into various forms without breaking. This property allows it to be crafted into intricate jewelry designs or thin foils for specific applications.
4. Ductility: Platinum is also ductile, meaning it can be drawn into thin wires without losing its strength. This property is important in applications where thin, flexible platinum wires are required, such as electrical contacts or electrodes.
5. Melting and Boiling Point: Platinum has an exceptionally high melting point of approximately 1,768 degrees Celsius (3,214 degrees Fahrenheit) and a boiling point of around 3,825 degrees Celsius (6,917 degrees Fahrenheit). These high temperatures make platinum resistant to melting or deforming under extreme heat conditions.
6. Hardness: Platinum is a relatively hard metal, although it is softer than some other precious metals like gold or silver. It has a hardness of approximately 4.5-5 on the Mohs scale, which measures a material’s resistance to scratching and abrasion.
7. Resistance to Corrosion: One of the most significant physical properties of platinum is its remarkable resistance to corrosion. It is highly inert and does not readily react with acids, alkalis, or other corrosive substances, making it suitable for applications where resistance to oxidation and chemical attack is crucial.

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Chemical Properties of Platinum

1. Reactivity: Platinum is a relatively inert metal, meaning it does not readily react with many substances under normal conditions. It is resistant to oxidation, corrosion, and tarnishing, making it highly durable and suitable for long-term use in different environments.
2. Catalytic Activity: Platinum is well-known for its excellent catalytic properties. It can act as a catalyst in various chemical reactions by facilitating the conversion of reactants into products without being consumed in the process. Platinum catalysts are widely used in industries such as petroleum refining, chemical manufacturing, and environmental control processes.
3. Hydrogen Absorption: Platinum has the ability to absorb and retain significant amounts of hydrogen gas. This property is utilized in hydrogen purification and storage applications, such as in fuel cells, where platinum catalysts enable efficient conversion of hydrogen and oxygen into electrical energy.
4. Alloys and Coordination Complexes: Platinum readily forms alloys with other metals, enhancing their properties and creating materials suitable for specific applications. Platinum alloys, such as platinum-rhodium and platinum-iridium, are used in the production of thermocouples, electrical contacts, and high-temperature equipment. Platinum also forms coordination complexes with various ligands, making it valuable in the field of coordination chemistry.
5. Acidic Behavior: Although platinum is generally considered an inert metal, it can exhibit acidic behavior under certain conditions. For example, it can dissolve in aqua regia, a mixture of nitric acid and hydrochloric acid, forming platinum(II) and platinum(IV) complexes.
6. Redox Reactions: Platinum can participate in redox (reduction-oxidation) reactions, where it can either gain or lose electrons. For example, platinum can be reduced from a higher oxidation state to a lower oxidation state by accepting electrons, or it can be oxidized by losing electrons in certain chemical reactions.

Uses of Platinum

1. Catalytic Converters: One of the most significant applications of platinum is in catalytic converters for automobiles. Platinum acts as a catalyst, facilitating the conversion of harmful gases, such as carbon monoxide, nitrogen oxides, and unburned hydrocarbons, into less harmful substances, such as carbon dioxide, nitrogen, and water vapor. Catalytic converters help reduce vehicle emissions and improve air quality.
2. Chemical Industry: Platinum is extensively used as a catalyst in various chemical reactions. It plays a vital role in processes such as petroleum refining, production of nitric acid, manufacturing of fertilizers, pharmaceutical synthesis, and many other industrial chemical processes. Platinum’s catalytic properties enhance reaction rates and selectivity, leading to more efficient and environmentally friendly processes.
3. Jewelry and Luxury Goods: Platinum’s rarity, durability, and attractive appearance make it highly valued in the jewelry industry. It is often used in the creation of high-quality jewelry, especially for engagement rings, wedding bands, and luxury accessories. Platinum’s white luster and resistance to tarnish make it an ideal choice for showcasing precious gemstones.
4. Electrical and Electronics: Platinum is used in various electrical and electronic applications due to its excellent electrical conductivity and resistance to corrosion. It is employed in electrical contacts, thermocouples, electrodes, and spark plugs. Platinum’s reliability and stability in high-temperature environments make it suitable for demanding electrical and electronic devices.
5. Medical Applications: Platinum finds applications in the medical field, particularly in the form of platinum-based drugs used in chemotherapy. Platinum-based compounds, such as cisplatin and carboplatin, are effective in treating certain types of cancer. Additionally, platinum is used in medical implants, including pacemakers and dental restorations, due to its biocompatibility and resistance to corrosion.
6. Glass Manufacturing: Platinum is utilized in glass manufacturing, specifically in the production of fiber optics and LCD (liquid crystal display) screens. Platinum’s high melting point and thermal stability make it an ideal material for glass electrodes and components that require precise control of temperature and conductivity.
7. Fuel Cells: Platinum plays a crucial role in fuel cell technology. It acts as a catalyst in proton exchange membrane fuel cells (PEMFCs) and solid oxide fuel cells (SOFCs), facilitating the electrochemical reactions that produce electricity from hydrogen and oxygen. Platinum’s catalytic properties and resistance to corrosion are essential for efficient fuel cell performance.

Conclusion

In conclusion, platinum is a highly valuable and versatile metal with a range of remarkable properties. Its rarity, durability, and attractive appearance make it highly sought after in the jewelry industry, where it is used to create exquisite pieces of high-quality jewelry. Additionally, platinum’s resistance to corrosion and high melting point make it an essential component in various industrial applications.

Platinum’s unique combination of physical, chemical, and catalytic properties make it an invaluable material with diverse applications across industries. Its scarcity, coupled with its remarkable characteristics, ensures its continued relevance and importance in various fields, driving technological progress, environmental sustainability, and the creation of luxurious goods.

Solved Example of Platinum

Example 1: A jewelry designer has a piece of platinum wire measuring 25 centimeters in length. The density of platinum is 21.45 grams per cubic centimeter. What is the mass of the wire?

Solution:

To find the mass of the wire, we need to know its volume. The volume of the wire can be calculated by multiplying its length by its cross-sectional area.

Assuming the wire has a circular cross-section, we can use the formula for the area of a circle:

A = πr2, where r is the radius of the wire.

Let’s say the wire has a radius of 0.2 centimeters (or 0.002 meters).

The cross-sectional area of the wire is A = π(0.002)2 = 0.00001257 square meters.

Now, we can calculate the volume of the wire: V = (length)(cross-sectional area) = (0.25 meters)(0.00001257 square meters) = 0.0000031425 cubic meters.

Finally, we can find the mass using the density formula:

mass = (density)(volume) = (21.45 g/cm³)(0.0000031425 m³)

= 0.0673 grams.

Therefore, the mass of the platinum wire is approximately 0.0673 grams.

Example 2: A catalyst manufacturer produces platinum catalysts in the form of small spheres. The average diameter of each platinum sphere is 0.5 millimeters. If the density of platinum is 21.45 grams per cubic centimeter, what is the volume of a single platinum sphere?

Solution:

The volume of a sphere can be calculated using the formula: V = (4/3)πr3, where r is the radius of the sphere.

The radius of the platinum sphere is half of its diameter, so r = 0.5 mm / 2

= 0.25 mm (or 0.025 centimeters).

Converting the radius to centimeters, we have r = 0.025 cm.

Now we can calculate the volume of the sphere: V = (4/3)π(0.025 cm)3 = 0.000065449 cm³.

Since the density of platinum is given as 21.45 g/cm³, the volume of the platinum sphere is equivalent to its mass.

Therefore, the volume of a single platinum sphere is approximately 0.000065449 cm³.

Frequently Asked Questions on Platinum

Is platinum more expensive than gold?

Yes, platinum is generally more expensive than gold. The price of platinum is determined by various factors, including its rarity, demand, and market conditions. Historically, platinum has been priced higher than gold due to its scarcity and unique properties.

What are the top 3 uses of platinum?

The top three uses of platinum are: a) Jewelry: Platinum is highly valued in the jewelry industry for its durability, beauty, and rarity. b) Catalytic Converters: Platinum is essential in catalytic converters, which reduce harmful emissions from vehicles. c) Chemical Industry: Platinum's catalytic properties find extensive use in various chemical processes, such as petroleum refining, pharmaceutical manufacturing, and fertilizer production.

What is the chemical name of Pt?

The chemical name of Pt is platinum. Platinum is a chemical element with the symbol Pt and atomic number 78.

Is platinum harmful to the human body?

Platinum is generally considered to be non-toxic and has low reactivity with biological systems. It is not known to have any essential biological function nor is it recognized as an essential nutrient. However, like any metal, platinum can be toxic at high concentrations or when in certain forms. Occupational exposure to high levels of platinum compounds or prolonged ingestion of platinum salts may have harmful effects on health. It is important to handle and use platinum and its compounds safely and follow appropriate safety guidelines.

Which is more costly diamond or platinum?

Diamonds and platinum have different pricing factors. While diamonds are valued based on their carat weight, cut, clarity, and color, platinum's price is primarily influenced by its weight and market conditions. In general, diamonds can be significantly more expensive than platinum, especially if they have high quality and large carat weights. However, the exact cost comparison depends on the specific characteristics and market factors of each diamond and platinum piece.

What is Colour of platinum?

Platinum has a naturally lustrous silver-white color. It is highly reflective and has a bright metallic appearance. This color is one of the reasons platinum is highly valued in jewelry, as it complements and enhances the beauty of gemstones.

Is platinum used in cars?

Yes, platinum is used in cars primarily in the form of catalytic converters. Catalytic converters contain platinum group metals, including platinum, palladium, and rhodium, which help convert harmful vehicle emissions into less harmful substances. Platinum's catalytic properties make it effective in facilitating these chemical reactions and reducing pollutants from exhaust gases.

Where is platinum found?

Platinum is a rare metal and is found in relatively low concentrations in the Earth's crust. The majority of the world's platinum deposits are located in South Africa, Russia, and Zimbabwe. Other countries, such as Canada, the United States, and Colombia, also have platinum reserves, but to a lesser extent. Platinum is typically obtained through mining and extraction processes from platinum-bearing ores and deposits.