Palladium
Definition and meaning of Palladium in chemistry.
![Palladium element card: symbol Pd, atomic number 46, atomic mass 106.42, electron configuration [Kr] 4d¹⁰, oxidation states +4 +2, Transition metal, group 10, period 5, solid at room temperature.](/assets/images/terms/palladium-chemical-element.webp)
Palladium is a rare, shiny, silvery-white metal with the chemical symbol Pd and atomic number 46. It belongs to the platinum group of metals and strongly resists chemical corrosion. Scientists widely recognize palladium for its amazing ability to speed up chemical reactions.
In more detail
You can find palladium in group 10 of the periodic table. It shares many physical and chemical traits with platinum, rhodium, ruthenium, iridium, and osmium. This dense transition metal has a very unique and special physical ability.
It can absorb up to 900 times its own volume of hydrogen gas at room temperature. When it absorbs this gas, the metal expands and forms a compound called palladium hydride. This sponge-like trait makes palladium extremely important for chemical synthesis and hydrogenation reactions.
Hydrogenation is a chemical process that adds hydrogen to other molecules. Engineers also use this gas-absorbing property to develop new fuel cell technologies. In nature, you can find pure, uncombined palladium metal sitting in river deposits.
Miners also extract it from magmatic sulfide ores alongside other platinum group elements. Palladium strongly resists reacting with oxygen at standard room temperatures. This resistance helps it keep its brilliant shine, high electrical conductivity, and solid strength.
If you heat palladium to 800 degrees Celsius in the air, a layer of palladium(II) oxide forms. However, the metal remarkably regains its shiny luster if you heat it even further. At higher temperatures, the dull oxide layer simply breaks down and disappears.
Key facts
| Field | General Chemistry |
|---|---|
| Symbol | Pd |
| Atomic number | 46 |
| Atomic mass | 106.42 u |
| Category | Transition-Metal |
| Melting point | 1554.9 °C |
| Year discovered | 1803 |
Car manufacturers use massive amounts of palladium to build catalytic converters for vehicle exhaust systems. A catalytic converter is a device that cleans up pollution from a car's engine. The palladium inside the device actively speeds up reactions between toxic exhaust gases. It forces deadly carbon monoxide and unburned fuel to react with oxygen in the hot exhaust. This fast reaction converts the toxic smog into harmless carbon dioxide gas and water vapor.
Frequently asked questions
Can palladium absorb hydrogen?
Yes, solid palladium metal can absorb massive amounts of hydrogen gas at room temperature. It acts like a sponge and forms a chemical compound known as palladium hydride.
Is palladium reactive with common acids?
Palladium does not react noticeably with most common acids at room temperature. However, it will dissolve slowly in hot, highly concentrated nitric acid and sulfuric acid.
Related terms
Sources & references
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