PALLADIUM
Palladium is a rare and lustrous silvery-white metal used by the natives of South and Mesoamerica before the arrival of the Europeans. As early as 1700, miners in Brazil were aware of a metal they called ouro podre, ‘worthless gold,’ which is a native alloy of palladium and gold.. It was identified in 1803 by the English chemist William Hyde Wollaston who purified it from ore samples from Colombia. He named it after the asteroid called “Pallas”. It belongs to the platinum group metals (PGM) along with platinum, iridium, ruthenium, osmium, and rhodium. It is the least dense of the platinum group metals followed by rhodium and ruthenium.
- Symbol: Pd
- Color: white
- Density: 12.02 g/cm³
- Atomic mass: 106.42
- Atomic number: 46
- Melting point: 1,554.9 °C
Notable properties
- Palladium is the most reactive of the platinum group metals; in its pure form it is the only one able to be attacked by nitric acid.
- At standard ambient temperature and pressure, palladium can absorb up to 900 times its volume in hydrogen.
- Solutions of palladium form an insoluble black precipitate of palladium iodide upon addition of iodide salts.
- Palladium can be precipitated from solutions by additions of dimethylglyoxime.
Uses
- Catalytic converters
- Jewelry
- Electronics