Nickel
Transition metal · Period 4 · Group 10 · d-block
The corrosion-resistant metal in coins, batteries and meteorites
- Atomic mass
- 58.693 u
- State at 25 °C
- Solid
- Electronegativity
- 1.91
- Melting point
- 1,454.9 °C
- Boiling point
- 2,729.9 °C
- Configuration
- [Ar] 3d8 4s2
Nickel, explained
Video lesson in production
Bhavya’s explainer for this element will play here.
Overview
Nickel ([Ar]3d8 4s2) is almost always found in the +2 oxidation state; dissolved Ni2+ ions give solutions a characteristic green color. The metal resists corrosion in air and water and is one of only four elements that are ferromagnetic at room temperature, along with iron, cobalt and gadolinium. Its surface readily adsorbs hydrogen and weakens the H–H bond, which makes finely divided nickel an excellent catalyst for adding hydrogen to unsaturated oils and other organic compounds.
About two-thirds of the nickel produced goes into stainless steel, where 8 to 10 percent nickel keeps the steel in its tough, nonmagnetic austenite form. Nickel-based superalloys hold their strength at the red-hot temperatures inside jet engines and gas turbines. Batteries are the fastest-growing use, since nickel-rich cathodes store more energy per kilogram. Earth's core is largely an iron–nickel alloy, and iron meteorites are made of the same mixture.
Discovery
Medieval German miners called a reddish ore Kupfernickel, roughly copper-demon, because it looked like copper ore but yielded no copper. In 1751 the Swedish chemist Axel Fredrik Cronstedt extracted a new white metal from this mineral, now known as nickeline (NiAs), and shortened the miners' name to nickel. Nickel was slow to win acceptance as an element, since many chemists suspected it was an alloy of known metals.
- Where it’s found
- Nickel is mined from sulfide ores such as pentlandite, in Canada and Russia, and from laterite ores in Indonesia, now the largest producer, and the Philippines and New Caledonia.
- What it’s used for
- Stainless steel
- Battery cathodes
- Jet-engine superalloys
- Coins
- Electroplating
- Hydrogenation catalysts
- In living things
- Nickel is not known to be essential for humans, but some plants and microbes require it, for example in the enzyme urease and in nickel–iron hydrogenases. Many people are allergic to it on skin contact.
- Safety
- Inhaled nickel compounds are known human carcinogens, and nickel tetracarbonyl is an extremely toxic, volatile liquid. Prolonged skin contact can cause allergic dermatitis.
How it compares
Where Nickel sits among all 118 elements on the trends that shape the table.
- Electronegativity1.91Pauling
#35 of 100 elements with data
- Ionization energy737kJ/mol
#42 of 104 elements with data
- Atomic radius135pm
#59 of 95 elements with data
- Electron affinity112kJ/mol
#24 of 109 elements with data
- Density8.91g/cm³
#47 of 114 elements with data
- Melting point1,730K
#33 of 110 elements with data
- Density
- 8.91 g/cm³
- Atomic radius
- 135 pm
- Covalent radius
- 110 pm
- Molar heat
- 26.07 J/(mol·K)
- Appearance
- lustrous, metallic, and silver with a gold tinge
- Discovered by
- Axel Fredrik Cronstedt
Inside the atom
28 electrons arranged in 4 shells: 2 · 8 · 16 · 2.
Orbital diagram
1s2 2s2 2p6 3s2 3p6 4s2 3d8 · shorthand [Ar] 3d8 4s2
- 1s2
- 2s2
- 2p6
- 3s2
- 3p6
- 4s2
- 3d8
Each box is an orbital holding up to two electrons of opposite spin. Highlighted subshells hold the valence electrons that decide how Nickel bonds.
Ionization energies
Signature reactions
The chemistry Nickel is known for.
Complex formation · Purification
Mond process
Impure nickel reacts with carbon monoxide to form volatile nickel tetracarbonyl, leaving other metals behind. Heating the gas reverses the reaction and deposits nickel that is more than 99.9 percent pure. Ludwig Mond discovered the reaction in 1890.
Conditions: forms at about 50 °C; decomposes at about 220 °C
Catalysis · Addition
Catalytic hydrogenation
Hydrogen adds across the carbon–carbon double bond on the nickel surface. The same chemistry turns liquid vegetable oils into solid fats for margarine and was recognized with Paul Sabatier's 1912 Nobel Prize.
Conditions: finely divided nickel catalyst, about 150 °C
Complex formation · Precipitation
Dimethylglyoxime test for nickel
Dimethylglyoxime forms a bright strawberry-red precipitate with nickel ions, even at very low concentrations. Ammonia is added to mop up the released hydrogen ions so the precipitate forms completely, making this a classic test and gravimetric method for nickel.
Conditions: slightly alkaline (ammonia-buffered) solution
Where you’ll meet it
Nickel (US coin)
The US five-cent piece is made of cupronickel, an alloy of 75 percent copper and 25 percent nickel.
Photo: Wikimedia Commons
Sudbury Basin
One of the world's largest nickel mining districts sits within this ancient impact structure in Ontario.
Photo: Wikimedia Commons
Iron meteorite
Iron meteorites are made of iron–nickel alloy, often with 5 to 30 percent nickel.
Photo: Wikimedia Commons
Pentlandite
Pentlandite, an iron–nickel sulfide, is the most important nickel ore mineral.
Photo: Wikimedia Commons
Research
No research on Nickel yet
When Bhavya publishes a project that studies Nickel, it will be linked here.