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Noble Metals

Noble metals: Ru, Rh, Pd, Ag, Os, Ir, Pt, Au; high E° (corrosion resistant)
Quick Reference
Formula / NotationNoble metals: Ru, Rh, Pd, Ag, Os, Ir, Pt, Au; high E° (corrosion resistant)
Also Known AsPlatinum group metals (PGMs), precious metals (Au, Ag, Pt), corrosion-resistant metals

What is Noble Metals?

Metals that are resistant to corrosion and oxidation in moist air, including gold, silver, platinum, palladium, rhodium, iridium, osmium, and ruthenium. Their resistance to chemical attack makes them valuable in jewelry, catalysts, and electrical contacts.

Formula & Notation

Noble metals: Ru, Rh, Pd, Ag, Os, Ir, Pt, Au; high E° (corrosion resistant)

Other Names / Synonyms: Platinum group metals (PGMs), precious metals (Au, Ag, Pt), corrosion-resistant metals

Properties & Characteristics

Noble metals are metals that resist chemical attack, corrosion, and oxidation in moist air. They typically have high standard electrode potentials (positive E°) and are found in the bottom right of the electrochemical series. The platinum group metals (PGMs: Ru, Rh, Pd, Os, Ir, Pt) plus silver and gold are considered noble metals. They form few compounds with common reagents and require strong oxidising media (aqua regia for Au and Pt; HNO₃ for Ag) for dissolution.

Uses & Applications

Noble metals are used in: catalysis (Pt and Pd in catalytic converters, Rh in auto catalysts, Pd in hydrogenation, Pt in fuel cells), jewellery (Au, Pt, Ag), electronics (Au in connectors, Ag in circuit boards), dentistry (Au, Pd alloys), medicine (Pt in cisplatin, Rh in radiotherapy), and as standards (Pt resistance thermometers, Pt-Ir mass standards).

Safety Information

Noble metals themselves are generally of low toxicity in metallic form. However, soluble forms (chloroplatinate(IV) salt, potassium tetrachloroaurate) can cause allergic sensitisation (platinum salt asthma). Platinum-based anticancer drugs (cisplatin) are highly toxic (nephrotoxicity, ototoxicity, nausea). PGM refinery workers are at risk of sensitisation.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Noble Metals
Formula Noble metals: Ru, Rh, Pd, Ag, Os, Ir, Pt, Au; high E° (corrosion resistant)
Synonyms Platinum group metals (PGMs), precious metals (Au, Ag, Pt), corrosion-resistant metals

Frequently Asked Questions

Metals that are resistant to corrosion and oxidation in moist air, including gold, silver, platinum, palladium, rhodium, iridium, osmium, and ruthenium. Their resistance to chemical attack makes them valuable in jewelry, catalysts, and electrical contacts.

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