What Is Nickel?

Nickel is a chemical element with the symbol Ni and atomic number 28, classified as a transition metal. It is a hard, corrosion-resistant, silvery-white metal widely used in stainless steel, coinage, and rechargeable batteries, valued especially for its ability to remain stable and resist tarnishing even after extended exposure to air and moisture.

The element's name comes from "Nickel," a shortened form of the German "Kupfernickel" (literally "Old Nick's copper" or "devil's copper") — a term used by miners who encountered ore that resembled copper deposits but couldn't actually be smelted to produce usable copper, leading them to blame the disappointing results on mischievous supernatural interference rather than recognizing it as an entirely different metal.

Nickel's electron configuration of [Ar] 3d⁸ 4s² places it among the ferromagnetic transition metals alongside iron and cobalt, though nickel's magnetic properties are somewhat weaker than iron's under typical conditions.

Physical & Chemical Properties

Nickel has an atomic mass of 58.693 u and a density of 8.908 g/cm³. It has a melting point of 1455°C and a boiling point of 2913°C.

Nickel is notably resistant to corrosion, maintaining a stable, tarnish-free appearance even after extended exposure to air, moisture, and many corrosive substances — a property that makes it valuable both for protective electroplating and for direct use in coins and other objects exposed to regular handling and environmental wear. Nickel is also one of the few elements that displays ferromagnetism at room temperature, though this magnetic property is somewhat weaker than that of iron, and is most commonly exploited in nickel-containing alloys rather than pure nickel metal itself.

Electron Configuration Explained

Nickel's electron configuration is [Ar] 3d⁸ 4s², giving it eight electrons in its 3d subshell alongside two electrons in the outer 4s orbital.

This near-complete d-subshell (eight out of a possible ten electrons) contributes to nickel's chemical stability and corrosion resistance, while still leaving enough unpaired electrons to produce measurable ferromagnetic behavior, similar in principle to iron and cobalt, though somewhat weaker in practical magnetic strength under typical conditions.

Nickel commonly forms a +2 oxidation state in its compounds, achieved by losing its two outer 4s electrons, a relatively simple and predictable pattern compared to some other transition metals that display a wider range of accessible oxidation states.

History & Discovery

Nickel-containing ores were encountered by miners for centuries before the element was formally identified, often mistaken for copper deposits due to superficial similarities in appearance, though smelting these ores using standard copper extraction methods produced disappointing, unusable results that miners attributed to supernatural mischief.

Swedish chemist Axel Fredrik Cronstedt successfully isolated and identified nickel as a distinct element in 1751, finally explaining the mysterious behavior that had frustrated and puzzled miners for generations. Nickel's broader industrial significance grew substantially in subsequent centuries, particularly with the development of stainless steel and various nickel-based alloys valued for their corrosion resistance and mechanical properties.

What Is Nickel Used For?

Nickel's corrosion resistance and alloying properties drive diverse modern applications:

  • Stainless steel: Nickel is commonly added to stainless steel alongside chromium, further improving corrosion resistance and overall mechanical properties compared to chromium-only stainless steel formulations.
  • Coins: Many coins worldwide, including portions of various national currencies, contain nickel due to its durability and corrosion resistance under frequent handling.
  • Batteries: Nickel is used in various rechargeable battery chemistries, including nickel-metal hydride batteries common in hybrid vehicles and nickel-cadmium batteries used in various electronic devices.
  • Magnets: Nickel's ferromagnetic properties, combined with iron and cobalt, contribute to certain magnetic alloy formulations.
  • Electroplating: A thin nickel coating is often applied to other metals to improve corrosion resistance and provide an attractive, durable finish.

Common Nickel Compounds

Nickel forms several industrially significant compounds:

  • Nickel sulfate: Used in electroplating processes to apply protective nickel coatings to other metals.
  • Nickel oxide: Used in ceramic glazes and as a component in certain battery chemistries.
  • Nickel-iron alloys: Combined with iron to create various specialized alloys valued for specific magnetic or mechanical properties.

Fun Facts About Nickel

  • The US five-cent coin, commonly called a "nickel," is actually composed primarily of copper (about 75%), with nickel making up only around 25% of its overall composition.
  • Nickel's name derives from a derogatory German mining term referencing supernatural mischief, reflecting the frustration miners felt when nickel-containing ore failed to yield usable copper through standard smelting techniques.
  • Nickel is one of only a few elements that displays ferromagnetism at room temperature, alongside iron and cobalt, though its magnetic strength is somewhat weaker than iron's under comparable conditions.
  • Some people develop skin allergies specifically to nickel, a relatively common metal allergy that can cause contact dermatitis from jewelry, watch straps, or other nickel-containing items.

Frequently Asked Questions

What is nickel's atomic number?
Nickel has atomic number 28, meaning each nickel atom contains 28 protons in its nucleus.

Why is the US 5-cent coin called a nickel if it's mostly copper?
The coin earned its nickname when it was first introduced containing a more substantial nickel content relative to other coins at the time. Despite copper making up the majority of its current composition, the "nickel" nickname has simply persisted through tradition.

Is nickel magnetic?
Yes, nickel is one of a small number of elements that exhibits ferromagnetism at room temperature, allowing it to be magnetized, though somewhat less strongly than iron under similar conditions.

Can you be allergic to nickel?
Yes, nickel allergy is one of the most common metal contact allergies, often causing skin irritation or dermatitis from prolonged contact with nickel-containing jewelry, belt buckles, or other everyday items.