Platinum Group Metals
Also: PGM, Platinum metals, Platinum group
Platinum group metals (PGMs) are six chemically related transition metals – platinum, palladium, rhodium, iridium, osmium and ruthenium – distinguished by exceptional corrosion resistance, high melting points and catalytic properties.
Platinum group metals (PGMs for short) form one of the most valuable and rarest metal groups on Earth. They comprise six elements that sit next to one another in the periodic table and display almost identical chemical behaviour: platinum (Pt), palladium (Pd), rhodium (Rh), iridium (Ir), osmium (Os) and ruthenium (Ru). Owing to their scarcity, industrial importance and price dynamics, PGMs are of global interest both as investment assets and as indispensable industrial raw materials – current prices are available in real time for platinum and palladium.
The six platinum group metals at a glance
| Metal | Symbol | Atomic number | Density (g/cm³) | Melting point (°C) | Main use |
|---|---|---|---|---|---|
| Platinum | Pt | 78 | 21.45 | 1,768 | Catalysts, jewellery, fuel cells |
| Palladium | Pd | 46 | 12.02 | 1,554 | Autocatalysts, electronics, hydrogen technology |
| Rhodium | Rh | 45 | 12.41 | 1,964 | Three-way catalysts (NOx reduction) |
| Iridium | Ir | 77 | 22.56 | 2,446 | Spark plugs, crucibles, electrodes |
| Osmium | Os | 76 | 22.59 | 3,033 | Hardening additive for alloys, science |
| Ruthenium | Ru | 44 | 12.45 | 2,334 | Hard-disk coating, electronics, catalysis |
At 22.59 g/cm³, osmium is the densest naturally occurring element of all – around three times heavier than iron.
Occurrence and extraction
PGMs occur extremely rarely in the Earth's crust; their average concentration is in the low ppb range (parts per billion). Around 70–75% of global PGM output comes from South Africa, above all from the Bushveld Igneous Complex in Limpopo Province – one of the geoscientifically most extraordinary deposits on Earth. Other significant producer countries are Russia (particularly Norilsk for palladium), Zimbabwe and Canada.
Extraction is predominantly carried out as by-product mining alongside nickel and copper mining. The ore grade is typically only a few grams per tonne of rock, which makes extraction elaborate and cost-intensive. From the raw ore, doré bars are produced first, which are then refined in refineries.
Alongside primary production, recycling (in particular from autocatalysts and electronic scrap) plays a growing role; for palladium, secondary material already covers a considerable share of demand.
Industrial importance
The most important single application for platinum, palladium and rhodium is the automotive exhaust catalyst. Three-way catalysts convert carbon monoxide, unburnt hydrocarbons and nitrogen oxides into less harmful compounds – without PGMs this process would not be economically feasible.
Further key applications:
- Hydrogen technology: Platinum is the central catalyst in proton-exchange-membrane fuel cells (PEM-FC), which gives PGMs special attention in the context of the energy transition.
- Electronics: Palladium in multilayer ceramic capacitors (MLCCs), ruthenium in hard-disk coatings.
- Chemical industry: Platinum and palladium as catalysts in nitric acid and sulphuric acid production.
- Medical technology: Platinum in pacemakers, electrodes and implant materials.
- Jewellery: Platinum (especially in Japan and the luxury segment) and palladium as a white-gold substitute.
Price formation and investment aspects
Unlike gold or silver, PGM prices are driven primarily by industrial demand. Rhodium, for instance, can experience extreme price swings – between 2020 and 2021 it temporarily traded above 20,000 USD per troy ounce, but then fell drastically. The high price volatility reflects the tight, geographically concentrated supply structure and the sensitive dependence on the automotive market.
The following investment forms are available: physical bars and coins (e.g. platinum coins), physically backed ETCs and certificates. Tax treatment (Capital Gains Tax, VAT on silver, platinum and palladium versus the VAT exemption of investment gold) differs by metal and jurisdiction – this is not tax or investment advice. Historical price developments can be tracked at Historical precious metal prices.
Distinction: PGMs vs. other precious metals
Although gold and silver are considered the best-known precious metals in everyday usage, they are not part of the platinum group. Compared with gold and silver, PGMs are distinguished by even higher melting points, greater hardness and much more pronounced catalytic activity. Common to all precious metals is resistance to corrosion by air and water and stability against most acids – PGMs, however, dissolve in aqua regia.
In brief
Platinum group metals are indispensable industrial raw materials with highly concentrated supply and price-determining demand from the automotive and technology industries – their scarcity and versatility make them a significant but volatile segment of the precious metals market.