Platinum is a chemical element with the symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal. Its name originates from Spanish platina, a diminutive of plata "silver". Platinum is a member of the platinum group of elements and group 10 of the periodic table of elements. It has six naturally occurring isotopes. It is one of the rarer elements in Earth's crust, with an average abundance of approximately 5 μg/kg. It occurs in some nickel and copper ores along with some native deposits, mostly in South Africa, which accounts for ~80% of the world production. Because of its scarcity in Earth's crust, only a few hundred tonnes are produced annually, and given its important uses, it is highly valuable and is a major precious metal commodity. Platinum is one of the least reactive metals. It has remarkable resistance to corrosion, even at high temperatures, and is therefore considered a noble metal. Consequently, platinum is often found chemically uncombined as native platinum. Because it occurs naturally in the alluvial sands of various rivers, it was first used by pre-Columbian South American natives to produce artifacts. It was referenced in European writings as early as the 16th century, but it was not until Antonio de Ulloa published a report on a new metal of Colombian origin in 1748 that it began to be investigated by scientists.

Platinum is used in catalytic converters, laboratory equipment, electrical contacts and electrodes, platinum resistance thermometers, dentistry equipment, and jewelry. Platinum is used in the glass industry to manipulate molten glass which does not "wet" platinum. As a heavy metal, it leads to health problems upon exposure to its salts; but due to its corrosion resistance, metallic platinum has not been linked to adverse health effects. Compounds containing platinum, such as cisplatin, oxaliplatin and carboplatin, are applied in chemotherapy against certain types of cancer. Pure platinum is currently less expensive than pure gold, having been so continuously since 2015, but has been twice as expensive or more, mostly prior to 2008. In early 2021, the value of platinum ranged from US$1,055 to US$1,320 per troy ounce.

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Atomic properties

Standard atomic weight195.084 ±0.009
Atomic mass195.084 u

Atomic radii

Radius (empirical)139 pm
Radius (calculated)177 pm
Covalent radius136 ±5 pm
Van der Waals radius175 pm

Atomic shell

Electron configurationXe 4f14 5d9 6s1
Ionization energy(1st) 8.95883 eV
(2nd) 18.56 eV
(3rd) 29 eV
(4th) 43 eV
(5th) 56 eV
Shell model

Physical properties

Density21.45 g·cm−3 (293.1 K)
Molar volume9.09·10-6 m3·mol−1
Speed of sound2,680 m·s−1


Melting point2,041 K
Boiling point4,098 K
Liquid range2,056 K


Melting enthalpy20 kJ·mol-1
Enthalpy of vaporization490 kJ·mol-1
Binding energy565 kJ·mol-1

Heat and conductivity

Specific heat capacity130 J·kg−1·K−1
Thermal conductivity72 W·m-1·K-1
Expansion coefficient8.8·10-6 K-1
Work function5.65 eV


Mohs hardness3.5
Brinell hardness392 NM·m-2
Vickers hardness549 NM·m-2

Elastic properties

Young’s modulus168 GPa
Shear modulus61 GPa
Bulk modulus230 GPa
Poisson’s ratio0.38

Electrical properties

Electrical conductivity9.48·106 S·m-1
Resistance1.06·10-7 Ωm


Magnetic susceptibility2.02·10-4 cm3·mol−1 (290 K)

Optical properties

Reflectivity73 %

Chemical properties

Basicityslightly basic
Oxidation state-2, 0, +2, +4, +6
Standard potential1.118 V (Pt2+ + 2e- → Pt)


Pauling scale2.28
Allred-Rochow scale1.44
Nagle scale1.49
Pearson absolute negativity5.6 eV

Other properties

Natural occurrenceprimordial
Crystal structureFace-centered cubic
Goldschmidt Classificationsiderophile
Superconductorwithout transition tempperature
Price/kg27,800 USD

Natural abundances

5 ppb ≈ 5.02·1010 M☉
9 ppb ≈ 1.79·1010 Mt
1,000 ppb ≈ 1 g
Earth’s crust
37 ppb ≈ 1,020 Mt