Nickel

Nickel is a silvery metal that makes 5p and 10p coins look nice, keeps stainless steel shiny, and provides the positive electrode in rechargeable batteries. Hidden in plain sight, it is also one of the most abundant elements inside the Earth: the planet's core contains enormous amounts of it, mixed with iron.

  • Atomic Number2828 protons, 28 electrons
  • Atomic Mass58.693 uAbout 58× heavier than hydrogen
  • State at Room TempSolidhard, silvery metal
  • Density8.912 g/cm³Similar density to cobalt
  • Melting / Boiling1454.8°C / 2912.8°CMelts at 1,455°C
  • Discovered1751Axel Fredrik Cronstedt, 1751

Nickel sits alongside cobalt and copper in Period 4.

These three transition metals have almost identical masses and share many uses in alloys and batteries.

Atomic Mass Comparison
Iron55.8 u
Cobalt58.9 u
Nickel58.7 u
Copper63.5 u
Zinc65.4 u

Nickel (58.7 u) and cobalt (58.9 u) are so close in mass they were extremely difficult to separate historically. Copper (63.5 u) just to the right is the first transition metal to show significant reddish colour in its pure form.

What is nickel?

Nickel is a transition metal in Group 10 of the periodic table. It has 28 protons and is magnetic, hard, shiny and very resistant to corrosion. It adopts primarily the +2 oxidation state, forming green or blue-green compounds. One of its most important properties is that it forms a wide range of useful alloys with other metals, particularly when corrosion resistance, high-temperature strength or magnetic properties are needed.

Nickel gets its name from the German Kupfernickel, "Devil's copper" or "Old Nick's copper", the miners' name for a reddish-brown ore (now called nickeline or niccolite) that looked like copper ore but yielded no copper. The miners blamed the devil for the deception. In 1751 the Swedish chemist Axel Fredrik Cronstedt extracted a new metal from this ore and named it nickel after the miners' curse. The symbol Ni comes directly from the name.

Fact The Earth's core contains more nickel than any other element except iron. Deep meteorites called iron meteorites, which represent material from the cores of ancient, shattered planetesimals, contain approx. 5-20% nickel mixed with iron. Almost all the nickel in the Earth's crust was originally delivered by nickel-iron meteorites bombarding the early Earth.

Where you find nickel

In space

Nickel is a major component of iron meteorites and is thought to be one of the main constituents of Earth's core. The Sun and most other stars contain nickel produced in stellar nucleosynthesis.

On Earth

Nickel makes up approx. 84 parts per million of the Earth's crust but is far more abundant in the core. Most crustal nickel was delivered by ancient meteorite bombardment.

  • Laterite ores. These are iron-rich, nickel-bearing soils formed by intense tropical weathering of nickel-containing rocks. They contain over 60% of global nickel reserves. Major producers include Indonesia, Philippines and New Caledonia.
  • Sulfide ores (pentlandite). Found in large deposits in Canada (Sudbury), Russia (Norilsk) and Australia. The Sudbury Basin in Ontario is thought to have formed from a massive meteorite impact that concentrated nickel-rich material.

How we use nickel

  • Stainless steel. Adding 8-10% nickel to chromium steel produces the most widely used grade of stainless steel (304 grade), found in kitchen sinks, cutlery, hospital equipment and food processing.
  • Batteries. Nickel metal hydride (NiMH) batteries were the main rechargeable technology before lithium-ion. Nickel is also a key component of advanced lithium-ion battery cathodes (NMC, nickel-manganese-cobalt).
  • Coins. Many coins worldwide contain nickel, including UK 5p and 10p coins (75% copper, 25% nickel). The US 5-cent "nickel" coin is 75% copper and 25% nickel.
  • Superalloys. Nickel-based superalloys withstand extreme temperatures and are used in the hottest sections of jet engines and gas turbines.
Did you know? The Sudbury Basin in Ontario, Canada: one of the world's largest nickel deposits, is almost certainly the scar left by a massive meteorite impact approx. 1.85 billion years ago. The impact melted the Earth's crust to a great depth, mixing in nickel from the asteroid and concentrating it in the rock that solidified afterwards. Mining the consequences of a prehistoric meteorite impact is one of geology's most remarkable stories.

How it was discovered

Nickel was isolated and identified as a new element in 1751 by the Swedish chemist Axel Fredrik Cronstedt. He was working with a copper-red ore from a copper mine that stubbornly refused to yield copper, and instead produced a strange white metal. By careful analysis, Cronstedt showed this was a genuinely new element and named it nickel after the miners' curse for the troublesome ore.

Deeper dive: nickel alloys, superalloys and nickel in the Earth's core

Nickel's corrosion resistance and ability to strengthen alloys make it one of the most versatile alloying metals. Monel, a nickel-copper alloy, is extraordinarily resistant to seawater corrosion and is used in marine applications. Invar, a nickel-iron alloy, barely expands or contracts with temperature change, making it ideal for precision instruments, pendulum clocks and the seals of LCD screens.

Nickel-based superalloys are among the most engineered materials in existence. They retain strength at temperatures above 1,000°C, close to their melting point, which allows jet engine turbine blades to operate in gases hotter than the melting point of many metals. The blades are cast as single crystals to eliminate grain boundaries where failure could start, and they are hollow inside, with intricate internal passages through which cooling air flows. Each blade may have taken years of research to design.

The Earth's inner core is thought to be mostly iron with approx. 5-6% nickel, based on the composition of iron meteorites (which represent ancient planetary cores), seismic wave speeds and density measurements. This nickel-iron core has been there since the planet formed 4.5 billion years ago, and it is responsible for generating Earth's magnetic field through convection in the liquid outer core.

Nickel is a versatile metal hiding in plain sight, in your coins, your cutlery and the Earth beneath your feet. Moving to 29 protons brings us to copper, one of the oldest metals in human history.