Nickel

This page is about the metal. For the United States 5 cent coin, see nickel (coin).

A chunk of nickel metal

Nickel (chemical symbol Ni) is a chemical element. It has an atomic number of 28 and an atomic mass of about 58.69amu. It has 28 protons. It is a transition metal.

Properties

Physical properties

Nickel is a silver-white metal. It is a little golden colored. It is easily polished (made shiny). It is magnetic. It is not magnetic when heated above 355 °C (671 °F). It is not soft like many other metals. It can be stretched into wires easily. It is not radioactive.

Chemical properties

Nickel is not a reactive metal. It dissolves slowly in acids. It does not rust like iron. It makes a thin coating of nickel(II) oxide which stops more corrosion. Aluminium does a similar thing.

Chemical compounds

Nickel(II) chloride

Nickel(II) sulfate

Nickel is found in two oxidation states: +2, nickel(II); and +3, nickel(III). Nickel(II) is more common. Nickel(III) also is common. Nickel in its +2 oxidation state is green. Nickel(II) chloride is a common +2 oxidation state compound. Nickel(II) oxide is normally dark green, but sometimes it is gray. This is because some of the nickel is in the +3 oxidation state (nickel(III). Nickel(III) compounds are oxidizing agents. They also are grayish. Nickel compounds can be green, blue, gray, or black.

Nickel(II) compounds

Nickel(II) compounds are not reactive. They are normally green or blue. They are toxic and irritate skin. Some of them are carcinogens.

• Nickel(II) carbonate, green
• Nickel(II) chloride, greenish
• Nickel(II) hydroxide, light green
• Nickel(II) nitrate, greenish
• Nickel(II) oxide, gray or light green
• Nickel(II) sulfate, blue-green

Nickel(III) compounds

Nickel(III) compounds are not well characterized (people don't know the properties of them). Some are black or gray.

• Nickel(III) oxide

Occurrence

Limonite, a common nickel ore

Nickel is not normally found as a metal in the ground. Sometimes meteorites have nickel and iron metal in them. Normally nickel is in minerals. Nickel hydroxides, sulfides, and silicates are common ores. Russia makes the most nickel.

History

Nickel was found when a copper-colored ore did not make copper metal. Later it was found out that the ore was actually a nickel ore. Nickel was isolated as a metal in 1751. At first, the copper colored nickel ore was the only source. Later, it was made as a byproduct of cobalt blue making.

Preparation

Nickel is made from sulfide ores. They are heated to melt them and concentrate them. They are also separated by oils. Nickel is made from its sulfide by heating it in air. This oxidizes the sulfide to sulfur dioxide, leaving liquid nickel behind. This nickel is not pure. Only about 75% of it is nickel.

Nickel can be made purer. It can react with carbon monoxide to make nickel carbonyl, a gas when warm. All the impurities are left behind. The nickel carbonyl is blown into nickel pellets, where it coats the pellets with pure nickel and puts out carbon monoxide. The carbon monoxide is reused (used again).

Another way to make the nickel pure is by dissolving it in an acid. Then it is electrolyzed to make nickel at the cathode.

Uses

As a metal

Stainless steel ball

Nickel is used in metal alloys. Stainless steel contains nickel. Nickel is also used in nichrome, a name for a nickel-chromium alloy. Nickel is used in coins such as nickels. It is used in magnets. Nickel is used in special expensive alloys called superalloys.

As chemical compounds

It is used in rechargeable batteries. They are also used to electroplate nickel on items. Nickel and some of its compounds are also used as a catalyst.

Safety

Nickel can irritate skin. That is why nickel jewelry is bad for some people. Some nickel salts are carcinogens. Nickel is not as toxic as other metals such as lead or mercury but it is still toxic.

Related pages

• Nickel compounds