Platinum group

Some metals are very special.

There are six metals in this group. They are often found together in the earth. They do not tarnish or wear away easily.

Because they stay shiny, people use them for jewelry.

Some are even used to make medicine.

These metals are also used in cars. They help clean the air from car exhausts. This helps keep the air safer for us.

Finding these metals can be hard. They are often found in rocks with nickel.

They are very useful in our world.

There are six special metals in the platinum group.

These metals are ruthenium, rhodium, palladium, osmium, iridium, and platinum. They are often found together in the same rocks. Scientists group them in two ways. Some belong to the iridium group. Others belong to the palladium group.

These metals are very strong. They do not wear away or tarnish easily. This makes platinum great for fine jewelry.

Some metals in this group help make medicine. They are also used in cars. They go into the exhaust system. These parts act as catalysts. A catalyst helps make a change happen faster. In a car, they turn bad gases into safer ones.

Finding these metals is hard work. They are often found in tiny amounts. Many are taken from nickel ore. People must process huge amounts of nickel to get them. This can hurt the environment. Mining can pollute water and soil. We must study how to use these metals safely.

The platinum-group metals are a special set of six metallic elements. They are found clustered together in the periodic table. These six metals are ruthenium, rhodium, palladium, osmium, iridium, and platinum.

They share many similar physical and chemical properties. Because of this, they often appear together in the same mineral deposits. Scientists group them into two smaller families based on how they behave in nature. One group is the iridium-group, which includes osmium, iridium, and ruthenium. The other is the palladium-group, which includes rhodium, platinum, and palladium.

These metals are very useful because they act as catalysts. A catalyst is something that helps a change happen more easily.

In cars, metals like platinum, palladium, and rhodium are used in exhaust systems. They help turn harmful gases like carbon monoxide into safer emissions. These metals are also very tough and do not tarnish easily. This makes platinum a great choice for fine jewelry. Other uses include making electronics, dental tools, and even anticancer drugs.

They are also used as chemical reagents in many different labs.

People have known about these metals for a very long time. Pre-Columbian Americans used platinum and platinum-rich alloys for many years. The first European mention of platinum was in 1557. A man named Julius Caesar Scaliger wrote about a mysterious metal in Central America. He said it was impossible to melt with Spanish tools at that time. The name platinum comes from the Spanish word "platina," which means "little silver." Spanish settlers in Colombia gave it this name because they thought it was just an unwanted impurity in their silver. Later, in 1815, scientists discovered rhodium, palladium, iridium, and osmium.

Finding these metals is a very big job because they are rare. They are often found in huge amounts of other rocks. For example, platinum is often found while processing nickel ore. Platinum might only make up two parts per million of that ore.

South Africa is the largest producer of platinum in the world. The Merensky Reef in the Bushveld Complex is a very important place for this. Other top producers include Russia, Canada, Zimbabwe, and the USA. Rhodium is especially hard to find in large amounts. In 2003, the whole world only produced about 7 or 8 tons of it.

Using these metals can sometimes cause problems for our world. Mining these metals can lead to water pollution and damage to the land. In Zimbabwe, mining caused acidic water drainage and environmental issues. Even the metals from car exhausts can cause trouble. Platinum can build up in the ground and in water. This is called bioaccumulation, where the metal moves through the food chain. This can eventually reach animals and humans. We must keep studying how to use these amazing metals safely.

The platinum-group metals, or PGMs, are a cluster of six precious metallic elements. These elements are transition metals located in the d-block of the periodic table. Specifically, they occupy groups 8, 9, and 10 across periods 5 and 6. The six metals are ruthenium, rhodium, palladium, osmium, iridium, and platinum. They are known as noble metals because they share similar physical and chemical properties. Because of these similarities, they often occur together in the same mineral deposits.

Scientists categorize these metals into two distinct subgroups based on their geological behavior. The first is the iridium-group platinum-group elements, or IPGEs. This group consists of osmium, iridium, and ruthenium. The second subgroup is the palladium-group platinum-group elements, known as PPGEs. This group includes rhodium, platinum, and palladium. Interestingly, the three elements located directly above the platinum group are iron, nickel, and cobalt. These three, along with the lanthanide gadolinium, are the only transition metals that show ferromagnetism near room temperature.

These metals are highly valued for their catalytic properties. A catalyst is a substance that helps a chemical reaction occur more easily. In the automotive industry, vehicle exhaust catalysts (VECs) use solid platinum, palladium, and rhodium. These are installed in exhaust systems to reduce harmful emissions. For example, they convert carbon monoxide (CO) into less harmful gases. Beyond cars, PGMs have many diverse applications. They are used in electronics, dentistry, and the production of anticancer drugs.

Platinum is also prized in fine jewelry because it is resistant to wear and tarnish. It possesses high mechanical strength, excellent high-temperature characteristics, and stable electrical properties.

Human history with these metals spans centuries. Pre-Columbian Americans used platinum and platinum-rich alloys long before European contact. The first European reference to platinum appeared in 1557. An Italian humanist named Julius Caesar Scaliger described a mysterious metal found in Central American mines. He noted that it was impossible to melt using Spanish methods of that time. The name "platinum" comes from the Spanish word "platina," meaning "little silver." Spanish settlers in Colombia used this name because they viewed the metal as an unwanted impurity in silver. Later, in 1815, rhodium and palladium were discovered by William Hyde Wollaston. His collaborator, Smithson Tennant, discovered iridium and osmium around the same time.

Extracting these metals is a complex and difficult process. Because they are often found in very low concentrations, they are frequently recovered as by-products. For instance, platinum is produced commercially during the processing of nickel ore. Even though platinum may only make up two parts per million of the ore, the massive volume of nickel processed makes recovery profitable.

Purification often begins with the anode residues from gold, copper, or nickel production. This is a very energy-intensive process. Classical methods use differences in chemical reactivity and solubility to separate the metals. Modern technology has moved toward using solvent extraction. To separate them, a sample might be dissolved in aqua regia to produce chloride complexes. These are then turned into specific compounds like volatile osmium tetroxide (OsO4) or ruthenium tetroxide (RuO4).

Geologically, these metals are found in specific environments. They are most common in mafic and ultramafic igneous rocks. These rocks have high concentrations of platinum-group elements, whereas granites have low amounts. The Bushveld Complex in South Africa is a major source, as its mafic layered intrusions outweigh all other geological settings. South Africa is the world's largest producer of platinum, followed by Russia. Other significant producers include Canada, Zimbabwe, and the United States. Rhodium is particularly rare; in 2003, the total annual world production was only 7 or 8 tons.

While these metals are useful, they also present environmental and health challenges. Mining can cause significant damage, such as the acidic water drainage and environmental degradation seen in Zimbabwe. There is also the concern of bioaccumulation. This occurs when metals like platinum enter water sources and soil, eventually moving up the food chain into animals and humans. Additionally, workers in industrial catalyst production may face health risks. Exposure to certain platinum salts can lead to allergic reactions, including dermatitis and asthma. As global demand for these metals rises, researchers continue to study how to manage these environmental impacts.