Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive, but large pieces are slow to react with air under standard conditions because a passivation layer of nickel oxide forms on the surface that prevents further corrosion. Even so, pure native nickel is found in Earth's crust only in tiny amounts, usually in ultramafic rocks, and in the interiors of larger nickel–iron meteorites that were not exposed to oxygen when outside Earth's atmosphere.

Meteoric nickel is found in combination with iron, a reflection of the origin of those elements as major end products of supernova nucleosynthesis. An iron–nickel mixture is thought to compose Earth's outer and inner cores. Use of nickel (as natural meteoric nickel–iron alloy) has been traced as far back as 3500 BCE. Nickel was first isolated and classified as an element in 1751 by Axel Fredrik Cronstedt, who initially mistook the ore for a copper mineral, in the cobalt mines of Los, Hälsingland, Sweden. The element's name comes from a mischievous sprite of German miner mythology, Nickel (similar to Old Nick). Nickel minerals were green, like copper ores, and were known as kupfernickel - Nickel's copper - because they produced no copper. An economically important source of nickel is the iron ore limonite, which is often 1–2% nickel. Other important nickel ore minerals include pentlandite and a mix of Ni-rich natural silicates known as garnierite. Major production sites include the Sudbury region, Canada (which is thought to be of meteoric origin), New Caledonia in the Pacific, and Norilsk, Russia.

Nickel is one of four elements (the others are iron, cobalt, and gadolinium) that are ferromagnetic at about room temperature. Alnico permanent magnets based partly on nickel are of intermediate strength between iron-based permanent magnets and rare-earth magnets. The metal is used chiefly in alloys and corrosion-resistant plating. About 68% of world production is used in stainless steel. A further 10% is used for nickel-based and copper-based alloys, 9% for plating, 7% for alloy steels, 3% in foundries, and 4% in other applications such as in rechargeable batteries, including those in electric vehicles (EVs). Nickel is widely used in coins, though nickel-plated objects sometimes provoke nickel allergy. As a compound, nickel has a number of niche chemical manufacturing uses, such as a catalyst for hydrogenation, cathodes for rechargeable batteries, pigments and metal surface treatments. Nickel is an essential nutrient for some microorganisms and plants that have enzymes with nickel as an active site.

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Atomic properties

Standard atomic weight58.6934 ±4·10-4
Atomic mass58.6934 u

Atomic radii

Radius (empirical)124 pm
Radius (calculated)149 pm
Covalent radius124 ±4 pm
Van der Waals radius163 pm

Atomic shell

Electron configurationAr 3d8 4s2
Ionization energy(1st) 7.639878 eV
(2nd) 18.168838 eV
(3rd) 35.187 eV
(4th) 54.92 eV
(5th) 76.06 eV
Shell model

Physical properties

Density8.908 g·cm−3 (293.1 K)
Molar volume6.59·10-6 m3·mol−1
Speed of sound4,970 m·s−1


Melting point1,728 K
Boiling point3,003 K
Liquid range1,275 K


Melting enthalpy17.2 kJ·mol-1
Enthalpy of vaporization378 kJ·mol-1
Binding energy431 kJ·mol-1

Heat and conductivity

Specific heat capacity444 J·kg−1·K−1
Thermal conductivity91 W·m-1·K-1
Expansion coefficient1.34·10-5 K-1
Work function5.15 eV


Mohs hardness4
Brinell hardness700 NM·m-2
Vickers hardness638 NM·m-2

Elastic properties

Young’s modulus200 GPa
Shear modulus76 GPa
Bulk modulus180 GPa
Poisson’s ratio0.31

Electrical properties

Electrical conductivity1.39·107 S·m-1
Resistance7.199·10-8 Ωm



Optical properties

Reflectivity72 %

Chemical properties

Basicityslightly basic
Oxidation state2, (-1), 0, 1, 3, 4
Standard potential-0.257 V (Ni2+ + 2e- → Ni)


Pauling scale1.91
Sanderson scale1.94
Allred-Rochow scale1.75
Ghosh-Gupta scale3.858 eV
Nagle scale1.47
Pearson absolute negativity4.4 eV

Other properties

Natural occurrenceprimordial
Crystal structureFace-centered cubic
Goldschmidt Classificationsiderophile
Superconductorwithout transition tempperature
Price/kg13.9 USD

Natural abundances

60,000 ppb ≈ 6.03·1014 M☉
80,000 ppb ≈ 1.59·1014 Mt
1.3·107 ppb ≈ 13 kg
Earth’s crust
90,000 ppb ≈ 2.49·106 Mt
2 ppb ≈ 2.74 Gt
Flowing water
0.3 ppb ≈ 4.8 kt
Human body
100 ppb ≈ 7 mg