Platinum
Platinum is a dense, silvery-white transition metal prized for being both strikingly unreactive and highly effective at speeding up chemical reactions it doesn't itself get consumed in. It resists tarnishing, corrosion, and most acids, which is why it's long been used for fine jewelry, and why it's become indispensable as a catalyst in modern industry.
- Group · Period
- 10 · 6
- At room temp
- solid
- Melts at
- 2041.55 K
- Density
- 21.46 g/cm³
- Discovered
- 1735
Uses
Platinum’s most important industrial role today is as a catalyst: it speeds up chemical reactions without being consumed, which is exactly what’s needed in a catalytic converter, where it helps break down pollutants from a car’s exhaust before they reach the air. The chemical industry relies on platinum catalysts for large-scale processes too, including refining petroleum and manufacturing certain acids. Platinum’s resistance to corrosion and high melting point also make it useful for laboratory equipment, high-temperature thermocouples, and fine electrical contacts that need to keep working reliably for years.
Beyond industry, platinum is a long-established choice for jewelry because of its rarity, weight, and resistance to tarnish, and certain platinum-based compounds, most famously cisplatin, are used as chemotherapy drugs to treat various cancers.
History
Indigenous peoples in what’s now Ecuador and Colombia were working with platinum long before Europeans encountered it, using it in metalwork alongside gold. Platinum entered the scientific record in Europe through Spanish naval officer and scientist Antonio de Ulloa, who came across it during a scientific expedition to South America that began in 1735 and documented the strange, hard-to-melt metal for European audiences. Because it was so difficult to purify and work with existing furnaces, platinum remained something of a curiosity for decades until better high-temperature techniques were developed, after which its usefulness as a catalyst and precious metal became clear.
Fun facts
- Platinum is denser than gold — a platinum ring is noticeably heavier than a same-sized gold one.
- Most of the world's platinum comes from just a couple of major mining regions, making its supply far more geographically concentrated than gold's.
- Platinum's name comes from the Spanish word platina, meaning 'little silver' — a somewhat dismissive nickname, since early Spanish colonists initially saw it as a worthless nuisance mixed in with silver ore.
Frequently asked questions
Why was platinum once considered worthless?
Spanish colonists in South America who were mining for silver and gold kept finding small grains of a heavy, dull-looking metal mixed in with their ore. It was extremely hard to melt with the technology of the time, so it couldn't easily be worked or sold, and it was sometimes discarded or even used to adulterate gold — the opposite of how precious it's considered today.
What is platinum's biggest modern use?
By volume, catalytic converters in vehicle exhaust systems are platinum's largest application. A small amount of platinum (often alongside palladium and rhodium) coats a ceramic honeycomb inside the converter and speeds up reactions that turn harmful exhaust gases into less harmful ones.
Is platinum rarer than gold?
Yes, platinum is generally considered rarer than gold in Earth's crust, and it's also much harder to mine and refine, which is part of why it commands a premium price in jewelry and industry alike, though the price relationship between the two metals shifts over time with demand.
Compounds
5 notable compounds containing Pt
- H2PtCl6acid
Chloroplatinic acid
A reddish-brown, highly water-soluble acid containing the hexachloroplatinate anion, typically handled as a hydrate and used as the entry point into most platinum chemistry.
Used for: Catalyst precursor in silicone curing and metal plating
- PtCl2(NH3)2pharmaceutical
Cisplatin
A square-planar platinum(II) complex bearing two ammonia and two chloride ligands arranged on the same side of the molecule, a geometry that is essential to how it binds and disrupts DNA.
Used for: Widely used chemotherapy drug for treating various cancers
- PtCl2salt
Platinum(II) chloride
An olive-green to brown, water-insoluble solid built from square-planar platinum(II) centers, occurring in polymeric chain or cluster forms depending on how it is prepared.
Used for: Precursor for platinum catalysts used in hydrosilylation reactions
- PtCl4salt
Platinum(IV) chloride
A reddish-brown solid with platinum in its +4 oxidation state, made by chlorinating platinum metal at high temperature and used as a gateway to many other platinum compounds.
Used for: Precursor for chloroplatinic acid and other platinum complexes
- PtO2oxide
Platinum(IV) oxide
A dark brown powder known commercially as Adams' catalyst, which is reduced in situ to finely divided platinum metal to drive hydrogenation reactions.
Used for: Catalyst for hydrogenating alkenes, alkynes, and other unsaturated groups
Isotopes
44 known isotopes
Swipe to see all columns →
| Isotope | Natural abundance | Half-life | Decay mode | Mass excess | Binding energy / nucleon | Decay width |
|---|---|---|---|---|---|---|
| Pt-190 | 0.012% | 4.97E11 Y | Alpha decay (100%) | -37,306.5 keV | 7,946.49 keV | 2.91 × 10-35 eV |
| Pt-192 stable | 0.782% | Stable | — | -36,288.53 keV | 7,942.49 keV | — |
| Pt-194 stable | 32.864% | Stable | — | -34,760.1 keV | 7,935.94 keV | — |
| Pt-195 stable | 33.775% | Stable | — | -32,793.88 keV | 7,926.55 keV | — |
| Pt-196 stable | 25.211% | Stable | — | -32,644.54 keV | 7,926.53 keV | — |
| Pt-198 stable | 7.356% | Stable | — | -29,904.02 keV | 7,914.15 keV | — |
Show all 44 isotopes
| Pt-165 | — | 0.26 ms | Alpha decay (100%) | -318 keV | 7,703 keV | 1.75 × 10-12 eV |
| Pt-166 | — | 300 us | Alpha decay (100%) | -4,783 keV | 7,733 keV | 1.52 × 10-12 eV |
| Pt-167 | — | 0.7 ms | Alpha decay (100%) | -6,753 keV | 7,746 keV | 6.52 × 10-13 eV |
| Pt-168 | — | 2.02 ms | Alpha decay (100%) | -11,010.08 keV | 7,773.62 keV | 2.26 × 10-13 eV |
| Pt-169 | — | 7.0 ms | Alpha decay (100%) | -12,464 keV | 7,784 keV | 6.52 × 10-14 eV |
| Pt-170 | — | 13.8 ms | Alpha decay (98%), Electron capture / beta-plus decay (2%) | -16,299.2 keV | 7,808.24 keV | 3.31 × 10-14 eV |
| Pt-171 | — | 45.5 ms | Alpha decay (90%), Electron capture / beta-plus decay (10%) | -17,466.57 keV | 7,816.6 keV | 1.00 × 10-14 eV |
| Pt-172 | — | 97.6 ms | Alpha decay (94%), Electron capture / beta-plus decay (6%) | -21,106.67 keV | 7,839.25 keV | 4.67 × 10-15 eV |
| Pt-173 | — | 382 ms | Alpha decay (86%), Electron capture / beta-plus decay (16%) | -21,936.76 keV | 7,845.39 keV | 1.19 × 10-15 eV |
| Pt-174 | — | 0.889 s | Alpha decay (76%), Electron capture / beta-plus decay (24%) | -25,317.61 keV | 7,866.11 keV | 5.13 × 10-16 eV |
| Pt-175 | — | 2.53 s | Alpha decay (64%), Electron capture / beta-plus decay (36%) | -25,708.68 keV | 7,869.52 keV | 1.80 × 10-16 eV |
| Pt-176 | — | 6.33 s | Electron capture / beta-plus decay (60%), Alpha decay (40%) | -28,933.92 keV | 7,888.99 keV | 7.21 × 10-17 eV |
| Pt-177 | — | 10.0 s | Electron capture / beta-plus decay (94.3%), Alpha decay (5.7%) | -29,370.44 keV | 7,892.49 keV | 4.56 × 10-17 eV |
| Pt-178 | — | 20.7 s | Electron capture / beta-plus decay (92.3%), Alpha decay (7.7%) | -31,997.49 keV | 7,908.25 keV | 2.20 × 10-17 eV |
| Pt-179 | — | 21.2 s | Electron capture / beta-plus decay (99.76%), Alpha decay (0.24%) | -32,268.13 keV | 7,910.68 keV | 2.15 × 10-17 eV |
| Pt-180 | — | 56 s | Electron capture / beta-plus decay (99.7%), Alpha decay (0.3%) | -34,429.88 keV | 7,923.58 keV | 8.15 × 10-18 eV |
| Pt-181 | — | 52.0 s | Electron capture / beta-plus decay (100%), Alpha decay (0.08%) | -34,381.5 keV | 7,924.13 keV | 8.77 × 10-18 eV |
| Pt-182 | — | 2.67 m | Electron capture / beta-plus decay (99.962%), Alpha decay (0.038%) | -36,168.42 keV | 7,934.75 keV | 2.85 × 10-18 eV |
| Pt-183 | — | 6.5 m | Electron capture / beta-plus decay (100%), Alpha decay (0.0096%) | -35,773.2 keV | 7,933.34 keV | 1.17 × 10-18 eV |
| Pt-184 | — | 17.3 m | Electron capture / beta-plus decay (100%), Alpha decay (0.001%) | -37,332.49 keV | 7,942.56 keV | 4.40 × 10-19 eV |
| Pt-185 | — | 70.9 m | Electron capture / beta-plus decay (100%) | -36,688.14 keV | 7,939.78 keV | 1.07 × 10-19 eV |
| Pt-186 | — | 2.10 h | Electron capture / beta-plus decay (100%), Alpha decay (0.00014%) | -37,864.45 keV | 7,946.81 keV | 6.03 × 10-20 eV |
| Pt-187 | — | 2.35 h | Electron capture / beta-plus decay (100%) | -36,685.36 keV | 7,941.17 keV | 5.39 × 10-20 eV |
| Pt-188 | — | 10.16 d | Electron capture / beta-plus decay (99.999974%), Alpha decay (0.000026%) | -37,820.97 keV | 7,947.9 keV | 5.20 × 10-22 eV |
| Pt-189 | — | 10.87 h | Electron capture / beta-plus decay (100%) | -36,469.41 keV | 7,941.4 keV | 1.17 × 10-20 eV |
| Pt-191 | — | 2.83 d | Electron capture (100%) | -35,698.34 keV | 7,938.73 keV | 1.87 × 10-21 eV |
| Pt-193 | — | 50 Y | Electron capture (100%) | -34,479.68 keV | 7,933.79 keV | 2.89 × 10-25 eV |
| Pt-197 | — | 19.8915 h | Beta-minus decay (100%) | -30,419.78 keV | 7,915.97 keV | 6.37 × 10-21 eV |
| Pt-199 | — | 30.80 m | Beta-minus decay (100%) | -27,388.7 keV | 7,902.3 keV | 2.47 × 10-19 eV |
| Pt-200 | — | 12.6 h | Beta-minus decay (100%) | -26,599.18 keV | 7,899.2 keV | 1.01 × 10-20 eV |
| Pt-201 | — | 2.46 m | Beta-minus decay (100%) | -23,740.71 keV | 7,885.83 keV | 3.09 × 10-18 eV |
| Pt-202 | — | 44 h | Beta-minus decay (100%) | -22,692.13 keV | 7,881.56 keV | 2.88 × 10-21 eV |
| Pt-203 | — | 22 s | Beta-minus decay (100%) | -19,510 keV | 7,867 keV | 2.07 × 10-17 eV |
| Pt-204 | — | 10.3 s | Beta-minus decay (100%) | -17,620 keV | 7,859 keV | 4.43 × 10-17 eV |
| Pt-205 | — | — | Beta-minus decay (100%), Beta-minus, neutron emission | -12,820 keV | 7,836 keV | — |
| Pt-206 | — | 160 ns | Beta-minus decay, Beta-minus, neutron emission | -9,240 keV | 7,820 keV | 2.85 × 10-9 eV |
| Pt-207 | — | — | Beta-minus decay (100%), Beta-minus, neutron emission | -4,140 keV | 7,797 keV | — |
| Pt-208 | — | — | Beta-minus decay (100%), Beta-minus, neutron emission | -500 keV | 7,780 keV | — |