Platinum Group Metals
Also: PGM, Platinum metals, Platinum group
Platinum group metals (PGM) 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 (PGM for short, from Platinum Group Metals) form one of the most valuable and rarest groups of metals on Earth. They comprise six elements that are neighbours in the periodic table and exhibit almost identical chemical behaviour: platinum (Pt), palladium (Pd), rhodium (Rh), iridium (Ir), osmium (Os) and ruthenium (Ru). Because of their scarcity, their industrial importance and their price dynamics, PGM are of global interest both as investment goods and as indispensable industrial raw materials – current prices are available for platinum and palladium in real time.
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 |
Osmium, at 22.59 g/cm³, is the densest naturally occurring element of all – and thus about three times heavier than iron.
Occurrence and extraction
PGM occur extremely rarely in the Earth's crust; their average concentration is in the low ppb range (parts per billion). Around 70–75% of the world's PGM output comes from South Africa, above all from the Bushveld Igneous Complex in Limpopo province – one of the most geologically exceptional deposits on Earth. Other significant producing countries are Russia (particularly Norilsk for palladium), Zimbabwe and Canada.
Extraction is predominantly carried out as by-product mining in nickel and copper mining. The ore grade is typically only a few grams per tonne of rock, which makes extraction laborious and costly. From the raw ore, doré bars are produced first, which are then refined in refineries.
Alongside primary mining, recycling (particularly from autocatalysts and electronic scrap) plays a growing role; for palladium, secondary material already covers a considerable share of demand.
Industrial significance
The most important single application for platinum, palladium and rhodium is the automotive exhaust catalyst. Three-way catalysts convert carbon monoxide, unburned hydrocarbons and nitrogen oxides into less harmful compounds – without PGM 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 PGM particular attention in the context of the energy transition.
- Electronics: palladium in multilayer capacitors (MLCCs), ruthenium in hard-disk coatings.
- Chemical industry: platinum and palladium as catalysts in the production of nitric and sulphuric acid.
- Medical technology: platinum in pacemakers, electrodes and implant materials.
- Jewellery: platinum (especially in Japan and the luxury segment) as well as 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 example, can experience extreme price swings – between 2020 and 2021 it was at times quoted at over 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.
For investors the following investment forms are available: physical bars and coins (e.g. platinum coins), physically backed ETCs as well as certificates. The tax treatment differs by metal and jurisdiction – in Malta, investment gold is VAT-exempt (Directive 2006/112/EC), whereas silver, platinum and palladium are subject to the standard VAT of 18%, and private disposals of movable assets are not subject to Maltese capital gains tax – this is not tax or investment advice. Historical price developments can be tracked under historical precious metal prices. Sources: cfr.gov.mt, legislation.mt, eur-lex.europa.eu.
Distinction: PGM vs. other precious metals
Although gold and silver are regarded in everyday usage as the best-known precious metals, they are not part of the platinum group. PGM are distinguished from gold and silver by even higher melting points, greater hardness and much more pronounced catalytic activity. What all precious metals have in common is resistance to corrosion by air and water as well as resistance to most acids – though PGM do dissolve in aqua regia.
In brief
Platinum group metals are indispensable industrial raw materials with a highly concentrated supply and price-determining demand from the automotive and technology industries – their scarcity and versatility make them a significant but price-volatile segment of the precious-metals market.