Palladium (Pd, element 46, CAS 7440-05-3) is a soft, silvery-white transition metal and one of the six platinum group metals. It is the lightest of the six at 12.007 g/cm³, it melts at 1,554.9 °C (1,828.05 K), and the world's mines produced about 190,000 kg (6,109 koz, thousand troy ounces) of it in 2025, 44.2% of that in Russia, according to USGS Mineral Commodity Summaries 2026. Its hydrogen uptake, its near-ferromagnetism and its central place in cross-coupling catalysis all trace back to one electron configuration, [Kr]4d¹⁰, that no other element shares.
What Is Palladium?#
Palladium is a platinum group metal in period 5, group 10 of the periodic table, with the symbol Pd and atomic number 46. Together with ruthenium, rhodium, osmium, iridium and platinum it makes up the platinum group metals, and with ruthenium and rhodium it forms the light triad of period 5. Palladium is a chemical element and a transition element: a d-block metal between rhodium (45) and silver (47), directly above platinum in group 10. Its state of matter at room temperature is solid, a face-centered cubic metal with a lattice constant of 389.02 pm at 20 °C that stays solid up to 1,554.9 °C.
Palladium Identity: Symbol, Atomic Number and CAS Number#
Palladium's identity numbers are symbol Pd, atomic number 46, CAS 7440-05-3 and standard atomic weight 106.42(1). The table lists the identity data used across DailyPlatinum, with the atomic weight from the IUPAC Commission on Isotopic Abundances and Atomic Weights (CIAAW).
| Attribute | Value |
|---|---|
| Symbol | Pd |
| Atomic number | 46 |
| CAS Registry Number | 7440-05-3 |
| Standard atomic weight (CIAAW) | 106.42(1), flagged "g" for variable isotopic composition |
| Period / group / block | 5 / 10 / d-block |
| Ground-state electron configuration | [Kr]4d¹⁰ |
| Crystal structure | Face-centered cubic, a = 389.02 pm at 20 °C |
| Common oxidation states | 0, +2, +4 (full range 0 to +5) |
| Electronegativity (Pauling) | 2.20 |
| First ionization energy | 804.4 kJ/mol |
The (1) in 106.42(1) is the uncertainty in the last digit. CIAAW gives palladium a "g" flag because its isotopic composition varies in nature; ruthenium and osmium carry the same flag, while rhodium, iridium and platinum do not. Suppliers also print CAS 7440-05-3 for palladium on carbon, where it identifies the palladium, not the supported catalyst.
Palladium Quick Facts#
Palladium's headline facts are its low density among the platinum group metals, its unique [Kr]4d¹⁰ electron configuration, and its central role in cross-coupling catalysis. The table sets nine of them out with the comparison that gives each one its meaning.
| Property | Palladium | Comparison |
|---|---|---|
| Density at 20 °C | 12.007 g/cm³ | Lightest platinum group metal; platinum 21.452 g/cm³ |
| Melting point | 1,554.9 °C (1,828.05 K; 2,830.8 °F) | Lowest of the six; platinum 1,768.3 °C |
| Boiling point | 2,963 °C (3,236 K) | Platinum 3,825 °C |
| Mohs hardness | 4.75 | Platinum 3.5 |
| Common oxidation states | 0, +2, +4 | Pd(0) drives cross-coupling catalysis |
| Magnetic susceptibility | +567.4 × 10⁻⁶ cm³/mol | Largest of any 4d or 5d element |
| Discovery | July 1802, William Hyde Wollaston | Named August 1802 after the asteroid 2 Pallas |
| Primary use | Autocatalysts, 8,227 koz of 10,140 koz demand in 2025 | Johnson Matthey, May 2026 |
| Mine production, 2025 | About 190,000 kg | USGS Mineral Commodity Summaries 2026 |
Palladium Properties#
Palladium is the lightest of the six platinum group metals and the only element with a filled-d-shell, no-outer-s-electron ground state. The constants here are modern CRC Handbook values; older Johnson Matthey tables, still copied across the web, give 12.02 g/cm³ for density and 76 W/(m·K) for thermal conductivity against the modern 12.007 g/cm³ and 71.8 W/(m·K).
Palladium Density: The Lightest Platinum Group Metal#
Palladium is the lightest platinum group metal, at 12.007 g/cm³, 44.0% less dense than platinum (21.452 g/cm³), the reason a palladium ring of the same size feels dramatically lighter than a platinum one. The ratio is 0.5597, so a palladium part weighs 56.0% of an identical platinum part.
Why is the gap so large when both metals share the same face-centered cubic structure? Platinum's atom carries 1.83 times palladium's mass (195.084 against 106.42) but is barely larger: the empirical atomic radii are 139 pm and 137 pm, and the lattice constants 392.36 pm and 389.02 pm. The lanthanide contraction and relativistic contraction keep the period 6 atom small, so the extra mass packs into almost the same volume. Palladium shares a 12.0-12.4 g/cm³ band with ruthenium and rhodium, while the heavy triad sits at 21.5-22.6 g/cm³. Weight, handling and use differences between the two group 10 metals are compared in platinum vs palladium.
Palladium Melting Point, Hardness and Reactivity#
Palladium melts at 1,554.9 °C (1,828.05 K) and is comparatively soft, at Mohs 4.75; it is not superconducting in pure bulk form at any measured temperature. Its melting point is the lowest of the six platinum group metals, 213.4 °C below platinum's, and it boils at 2,963 °C (3,236 K). Vickers hardness runs 400-600 MPa and Young's modulus is 121 GPa, so palladium, like platinum, can be worked hot or cold. Its thermal expansion, 11.77 × 10⁻⁶ K⁻¹, is 31.8% higher than platinum's, so the two metals are not interchangeable in sealed assemblies.
How reactive is palladium? It does not react with oxygen at room temperature, yet it dissolves readily in aqua regia, slowly in concentrated nitric acid and in hot concentrated sulfuric acid. Hydrogen changes it most: palladium hydride superconducts above a hydrogen-to-palladium ratio of about 0.75, reaching about 9 K near PdH₁.
Palladium Electron Configuration, Oxidation States and Magnetism#
Palladium's ground state, [Kr]4d¹⁰, is unique among all elements in ending with a filled d-shell and no outer s-electron; its common oxidation states are 0, +2 and +4, with Pd(0) central to its catalytic chemistry. A naive filling order predicts 4d⁸5s², and the observed configuration is the root of palladium's hydrogen uptake and magnetism. Pd(0) is the working state of cross-coupling catalysts, Pd(II) carries most commercial salts, and Pd(IV) appears in PdO₂ and PdF₄. PubChem's "common" field lists +3 and +2, which includes the rare +3 state and omits both 0 and +4.
Palladium is paramagnetic, with a molar susceptibility of +567.4 × 10⁻⁶ cm³/mol at 288 K, 2.8 times platinum's, and a Stoner factor near 1 places it close to ferromagnetic instability. Hydrogen is the other signature: palladium absorbs up to 900 times its own volume of hydrogen and stays ductile as non-stoichiometric PdHₓ (x < 1). Its lattice grows from 388.9 pm to 402.5 pm between the α- and β-phases, about 3.4% linear, so palladium hydrogen membranes run above 300 °C to avoid the jump.
Where Palladium Comes From#
Palladium comes mainly from South Africa's Bushveld Complex and Russia's Noril'sk-Talnakh nickel-copper deposit, which between them supply most of the world's output. Russia and South Africa produced 154,000 kg of the world's 190,000 kg of mined palladium in 2025, or 81.1%, on USGS Mineral Commodity Summaries 2026 estimates. Where does the US get palladium? One Montana company mines it, but imports met 57% of US needs in 2025, coming in 2021-2024 from South Africa (37%), Russia (36%), Belgium (6%), Canada (6%) and other countries (15%), according to the same USGS report.
Palladium Ore and Minerals#
Unlike platinum, which occurs almost entirely as discrete platinum-group minerals, palladium is partly locked inside the base-metal sulfide pentlandite, making palladium recovery partly a flotation problem rather than a liberation problem. Pentlandite, (Fe,Ni)₉S₈, is the principal sulfide host of palladium and rhodium in solid solution, while pyrrhotite holds no palladium. At the Main Sulfide Zone of Zimbabwe's Great Dyke about 80% of the palladium sits in pentlandite, as Oberthür and co-workers found (summarized in the Journal of the SAIMM, 2013).
Why do deposits differ in their palladium content? Magma chemistry sets the ratio. Bushveld reef sulfide carries platinum and palladium at roughly 2:1, while Noril'sk sulfide carries palladium and platinum at 2.5-5:1, because extreme fractional crystallization concentrated palladium into late copper-rich ores. USGS Professional Paper 1802-N (2017) grades the Talnakh cuprous ore at 8.49 g/t palladium against 2.11 g/t platinum.
Palladium Supply and Production#
Russia supplied 44.2% of world mined palladium in 2025 (84,000 kg of 190,000 kg), against South Africa's 36.8%, according to USGS Mineral Commodity Summaries 2026; Russian output is a nickel-mining by-product, so it follows nickel economics rather than palladium prices. The table gives USGS mine production for 2024 and the 2025 estimate, in kilograms of contained palladium.
| Country | 2024 (kg) | 2025 estimate (kg) | Share of 2025 world total |
|---|---|---|---|
| Russia | 89,000 | 84,000 | 44.2% |
| South Africa | 82,600 | 70,000 | 36.8% |
| Canada | 17,000 | 16,000 | 8.4% |
| Zimbabwe | 15,200 | 15,000 | 7.9% |
| United States | 10,200 | 6,200 | 3.3% |
| Other countries | 2,870 | 2,900 | 1.5% |
| World (rounded) | 217,000 | 190,000 | 100% |
World output fell 12.4% between the two years, from 217,000 kg (6,977 koz) to 190,000 kg (6,109 koz). USGS ties the US decline to one operation remaining on care and maintenance, and its country lines sum to 194,100 kg against the rounded world total, so the shares add to slightly more than 100%. Demand, recycling and the annual balance are tracked on the palladium market page.
Supply shocks have moved the metal before. Russian export delays in the run-up to 2000 set off a squeeze; when prices collapsed in early 2001, Ford Motor Company booked a loss of nearly US$1 billion on palladium it had stockpiled. The LBMA palladium price fell 58.1% during calendar 2001, from US$1,050 to US$440 per troy ounce.
Palladium Discovery and History#
Palladium was discovered in July 1802 by William Hyde Wollaston, who sold it anonymously from a Soho shop in April 1803 as "new silver" before disclosing his own authorship in 1805. Working with Smithson Tennant on South American crude platinum, he dissolved the ore in aqua regia, precipitated the platinum as ammonium chloroplatinate and treated the remaining solution with mercuric cyanide, then heated the palladium(II) cyanide to the metal. He named the element in August 1802 after the asteroid 2 Pallas, which Heinrich Wilhelm Olbers had found on 28 March 1802, four to five months earlier.
The anonymous sale invited a challenge. Richard Chenevix published a paper in 1803 arguing that palladium was an alloy of platinum and mercury, and received the Royal Society's Copley Medal that year. Wollaston, still anonymous, offered £20 for 20 grains of palladium made by Chenevix's route. Nobody collected, and in 1805 Wollaston revealed his identity and showed palladium to be a distinct element. PubChem gives 1803, the year of the first sale, as the discovery year.
Palladium Uses, Compounds and Alloys#
Palladium's uses rest on three properties: catalytic activity, hydrogen uptake and a silvery-white metal that alloys readily. Autocatalysts take most of the metal, chemistry uses the compounds, and dentistry and jewelry use the alloys.
What Is Palladium Used For?#
Palladium's largest modern use is autocatalysts, and its most cited scientific use is palladium cross-coupling catalysis, the reaction family that won Richard Heck, Ei-ichi Negishi and Akira Suzuki the 2010 Nobel Prize in Chemistry. Automotive catalysts took 8,227 koz of the 10,140 koz of palladium demand in 2025, or 81.1%, in Johnson Matthey's PGM Market Report of May 2026. Jewelry took only 83 koz. The table dates each use.
| Use | What palladium does | In use since |
|---|---|---|
| Dentistry | Palladium-silver and palladium-copper dental alloys, still material in Japan and Germany | 19th to 20th century |
| Hydrogen purification membranes | Palladium and palladium-silver membranes rely on the metal's hydrogen uptake | 20th century |
| Palladium white gold | Whitening alloy for gold that avoids nickel | 1939 |
| Autocatalysts | Two-way catalysts from 1975, three-way from 1977; converter demand rose from about 100 t in 1990 to nearly 300 t in 2000 | 1975 |
| Cross-coupling catalysis | Carbon-carbon and carbon-nitrogen bond formation | 1972 |
| Multilayer ceramic capacitors | Electrode metal in electronics | 1980s |
The six named palladium cross-coupling reactions are listed below with the year each was reported.
- Heck reaction, 1972
- Sonogashira reaction, 1975
- Negishi reaction, 1977
- Stille reaction, 1978
- Suzuki reaction, 1979
- Buchwald-Hartwig amination, 1994
Palladium leaves refineries as sponge, the fine granular form that the London Platinum and Palladium Market (LPPM) accredits and Johnson Matthey prices; purity grades and specifications of palladium powder have their own page.
Palladium Compounds#
The single most used homogeneous palladium catalyst is palladium(II) acetate, Pd(CH₃COO)₂, the workhorse of Heck, Suzuki and Buchwald-Hartwig coupling. Palladium(II) chloride is the master precursor from which most other palladium compounds are made. The table lists five core compounds with the CAS numbers DailyPlatinum prints.
| Compound | Formula | CAS | Primary use |
|---|---|---|---|
| Palladium(II) chloride | PdCl₂ | 7647-10-1 | Master precursor; Wacker process, CO detection, electroless plating |
| Palladium(II) acetate | Pd(CH₃COO)₂, trimeric Pd₃(OAc)₆ in the solid | 3375-31-3 | Heck, Suzuki, Buchwald-Hartwig, carbonylation, C-H activation |
| Tetrakis(triphenylphosphine)palladium(0) | Pd(PPh₃)₄ | 14221-01-3 | Archetypal Pd(0) cross-coupling catalyst; highly air-sensitive |
| Palladium on carbon | Pd/C, typically 1-10 wt% Pd | 7440-05-3 (identifies the palladium) | Heterogeneous hydrogenation; supplied water-wet for fire safety |
| Palladium(II) nitrate | Pd(NO₃)₂ | 10102-05-3 | Chloride-free impregnation of autocatalyst washcoats |
Palladium(II) chloride reacts with carbon monoxide and water to deposit palladium metal (PdCl₂ + CO + H₂O → Pd + CO₂ + 2 HCl), the reaction behind CO detection tubes. Structure, CAS and handling data for the two most used salts sit on the palladium(II) acetate and palladium(II) chloride pages.
Palladium Alloys#
Palladium alloys with silver and copper in dentistry, and 5% palladium (Pt950/Pd) is the softest common platinum jewelry alloy, added to harden and lighten pure platinum. Pt950/Pd reaches about 60 HV annealed against about 40-41 HV for pure platinum, and Pt850/Pd about 90 HV (substech.com, a secondary source). In gold, palladium has whitened palladium white gold since 1939, a nickel-free alternative that needs no rhodium plating. Alloys in which palladium is the main metal, rather than an additive, are covered under palladium jewelry.
Palladium Isotopes and Radioactivity#
Palladium has six naturally occurring isotopes, palladium-102, 104, 105, 106, 108 and 110, so it is polyisotopic, unlike its neighbor rhodium with its single isotope. Palladium-106 is the most abundant at 27.3%, followed by palladium-108 at 26.5%; palladium-102 is the rarest at 1.02%.
Is palladium radioactive? Natural palladium is not, but two artificial isotopes matter. Palladium-103, half-life 16.991 days, decays by electron capture and emits 20-23 keV X-rays, which suits permanent seed implants for prostate cancer and uveal melanoma. Palladium-107 is the second-longest-lived fission product known, with a half-life of 6.5 million years and a yield of about 0.14% per uranium-235 fission, so palladium recovered from spent nuclear fuel needs isotopic separation before consumer use.
Is Palladium Toxic?#
Palladium has no listed OSHA, NIOSH or ACGIH occupational exposure limit, the same status as iridium and ruthenium. OSHA's annotated Table Z-1, checked on 6 August 2026, has no entry for palladium, whereas platinum metal carries 1 mg/m³ and soluble platinum salts 0.002 mg/m³ as an 8-hour average. No limit does not make every compound benign. PubChem's GHS data classify palladium(II) chloride as "Danger", including H301 (toxic if swallowed) and H317 (may cause an allergic skin reaction), and palladium(II) acetate as "Danger", including H317 and H318 (causes serious eye damage).
How Rare Is Palladium?#
Palladium is rare, yet it is the most-mined platinum group metal: world mine production was about 190,000 kilograms in 2025, ahead of platinum's 170,000 kg on the same USGS Mineral Commodity Summaries 2026 basis. Against the four minor platinum group metals the gap is wide. On Johnson Matthey's May 2026 figures, 2025 primary palladium supply of 6,589 koz was 9.4 times rhodium's 701 koz (21.8 t), and osmium output is only about 500-550 kg a year (SFA Oxford for the International Platinum Group Metals Association, May 2026). Recycling adds a second source: USGS reports about 50,000 kg recovered from US catalytic converters alone in 2025.
Explore Palladium#
Palladium's current price and its attribute pages sit on their own dedicated pages, listed below with the other five platinum group metals.
Palladium Price Today#
Palladium and platinum are the only two platinum group metals with an LBMA benchmark auction and NYMEX futures contract. The LBMA Palladium Price is auctioned twice each London business day, immediately after each platinum auction, and ICE Benchmark Administration has run it since 1 July 2026. The live palladium price today per troy ounce, gram and kilogram is on palladium price today.
Four further pages cover the other palladium price series and units, listed below.
- History: the palladium price chart, with live and historical prices
- Exchange: palladium futures, the NYMEX contract of 100 troy ounces
- Benchmark: LBMA platinum and palladium prices, how the auction sets them
- Units: the troy ounce converter, at 31.1034768 g per troy ounce
Palladium Attribute Pages#
Palladium's attribute pages take each section of this page to full depth. The table lists the 13 pages with the headline value each one expands.
| Attribute page | Headline value on this page |
|---|---|
| Palladium properties | Physical and chemical constants in one set |
| Palladium density | 12.007 g/cm³ at 20 °C |
| Palladium melting point | 1,554.9 °C; boils at 2,963 °C |
| Palladium electron configuration | [Kr]4d¹⁰; oxidation states 0, +2, +4 |
| Palladium uses | Autocatalysts, 81.1% of 2025 demand (Johnson Matthey) |
| Palladium occurrence | Pentlandite; Bushveld and Noril'sk-Talnakh |
| Palladium discovery | Wollaston, July 1802 |
| Palladium isotopes | 6 natural isotopes; palladium-107 lasts 6.5 million years |
| Palladium compounds | Pd(OAc)₂, PdCl₂, Pd(PPh₃)₄, Pd/C |
| Palladium alloys | Dental alloys; Pt950/Pd |
| Palladium toxicity | No OSHA, NIOSH or ACGIH limit |
| Is palladium magnetic | Paramagnetic, +567.4 × 10⁻⁶ cm³/mol |
| How rare palladium is | About 190,000 kg mined in 2025 (USGS) |
Other Platinum Group Metals#
Palladium's five sister metals share its ores and refineries but differ sharply in density, output and price series. The table lists them by atomic number.
| Metal page | Atomic number | Density at 20 °C (g/cm³) | Relation to palladium |
|---|---|---|---|
| Ruthenium (Ru), element 44 | 44 | 12.364 | Light triad, period 5 |
| Rhodium (Rh), element 45 | 45 | 12.423 | Period 5 neighbor; also hosted in pentlandite |
| Osmium (Os), element 76 | 76 | 22.587 | Heavy triad; densest element |
| Iridium (Ir), element 77 | 77 | 22.562 | Heavy triad |
| Platinum (Pt), element 78 | 78 | 21.452 | Directly below palladium in group 10 |
Supply, demand and balances for all six metals, with Johnson Matthey and WPIC figures kept apart, sit in the platinum group metals market section.
Palladium FAQ#
What is palladium used for?#
Palladium is used mainly in autocatalysts, cross-coupling catalysis, dentistry, hydrogen-purification membranes and multilayer ceramic capacitors. The main demand sectors are listed below with Johnson Matthey's 2025 figures.
- Autocatalysts: 8,227 koz
- Electrical and electronics, including capacitors: 535 koz
- Chemical, including cross-coupling catalysts: 519 koz
- Dental and biomedical: 163 koz
Is palladium toxic?#
Palladium has no listed occupational exposure limit; OSHA's Table Z-1 has no entry for it, and neither NIOSH nor ACGIH lists one. The documented hazards sit with compounds. PubChem's GHS data classify palladium(II) chloride as toxic if swallowed (H301) and as a skin sensitizer (H317), and palladium(II) acetate as causing serious eye damage (H318).
Is palladium magnetic?#
Palladium is the most paramagnetic element in the platinum group metals, at +567.4 × 10⁻⁶ cm³/mol, close enough to ferromagnetic instability that small amounts of dissolved iron, cobalt or nickel can push its alloys into true ferromagnetism. Pure palladium is not ferromagnetic at any temperature.
Why is palladium lighter than platinum?#
Palladium is lighter than platinum because its atoms are about the same size as platinum's but carry only 55% of the mass: 106.42 against 195.084. The lanthanide contraction and relativistic effects keep platinum's atom small, so its lattice constant (392.36 pm) barely exceeds palladium's (389.02 pm). The result is 12.007 g/cm³ against 21.452 g/cm³, a 44.0% difference.
Is palladium rare?#
Palladium is rare but the most-mined platinum group metal: world mine production was about 190,000 kilograms (6,109 koz) in 2025, against 170,000 kg of platinum, on USGS Mineral Commodity Summaries 2026 figures. Primary palladium supply was 9.4 times rhodium's in 2025 on Johnson Matthey's basis.
Who discovered palladium?#
Palladium was discovered by William Hyde Wollaston in July 1802, who named it in August 1802 after the asteroid 2 Pallas, found by Heinrich Wilhelm Olbers four to five months earlier. He proved it a distinct element in 1805, after Richard Chenevix had called it an alloy of platinum and mercury.