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Nickel is a lustrous silvery-white metal with a silver-white tint of pale gold. Nickel is a transition metal, hard, ductile. The chemical activity of pure nickel is quite high, which can be seen in the powder state of the reaction surface area, but the bulk nickel metal reacts slowly with the surrounding air because a layer of oxide with protective properties has been formed on its surface. Even so, because the activity between nickel and oxygen is high enough, it is difficult to find natural metallic nickel on the earth's surface. The natural nickel on the earth's surface is sealed in larger nickel-iron meteorites because meteorites do not have access to oxygen when they are in space. On Earth, this natural nickel is always combined with iron, which reflects the fact that they are the main end products of supernova nucleosynthesis. It is generally believed that the earth's core is composed of a mixture of nickel and iron.

Source

The use of nickel (a natural meteoric nickel-iron alloy) dates back to 3500 BC. Axel Frederick Cronsteit first isolated nickel in 1751 and defined it as a chemical element, although he initially mistook nickel ore for a mineral of copper. The foreign name of nickel comes from the mischievous goblin of the same name in the legend of German miners (Nickel, which is similar to the devil's nickname "Old Nick" in English). This is because nickel and copper mines cannot produce copper by smelting copper, so they are compared to demons. The most economical source of nickel is iron ore limonite, which generally contains 1-2% nickel. Other important minerals of nickel include magnesite and nickel pyrite. Major nickel producers include the Soderberry region of Canada (generally considered to be a meteorite impact crater), New Caledonia in the Pacific Ocean and Norilsk in Russia.

Since nickel oxidizes slowly at room temperature, it is generally considered to have corrosion resistance. Historically, nickel has been used to plate various surfaces, such as metals (such as iron and brass), the interior of chemical devices, and certain alloys (such as nickel silver) that need to maintain a shiny silver shine. About 6% of the world's nickel production is still used for corrosion-resistant pure nickel plating. Nickel used to be a common ingredient in coins, but this aspect has been largely replaced by cheaper iron, especially because some people have skin allergies to nickel. Despite this, the UK began using nickel minted coins in 2012, despite opposition from dermatologists.

Only four elements are ferromagnetic at room temperature, and nickel is one of them. The nickel-containing alnico permanent magnet has a magnetic strength between the iron-containing permanent magnet and the rare earth magnet. The status of nickel in the modern world mainly comes from its various alloys. About 60% of the world's nickel production is used in the production of various nickel steels (especially stainless steels). Other common alloys, as well as some new high-temperature alloys, account for almost all of the rest of the world's nickel consumption. Chemical uses for making compounds account for less than 3% of nickel production [5]. As a compound, nickel has several specific uses in chemical manufacturing, for example as a catalyst for hydrogenation reactions. Some microbial and plant enzymes use nickel as an active site, so nickel is an important nutrient for them.

Characteristics

atomic and physical properties

Nickel is a lustrous silvery-white metal, its silvery-white with a hint of pale gold, which can be highly polished. Only four elements are ferromagnetic at or near room temperature, nickel being one of them, the other three being iron, cobalt and gadolinium. Its Curie temperature is 355 ° C., that is, large blocks of nickel lose their magnetic properties above this temperature.

Electronic Arrangement Controversy

Nickel atoms share two electron arrangements:[Ar] 4s2 3d8 and [Ar] 4s1 3d9, and the energies of the two are very close (the symbol [Ar] refers to its core structure being similar to argon). There is still disagreement as to which arrangement has the lower energy. Chemistry textbooks cite the nickel electron arrangement as [Ar] 3d8 4s2 or the same [Ar] 4s2 3d8 as the former. This arrangement follows the Madelung energy ordering rule, predicting that the 4s position will be filled before the 3d position is filled. This is supported by experiments, and the lowest energy state of the nickel atom is the 4s2 3d8 energy order.

However, both arrangements actually give rise to a series of states with different energies. These two sets of energies overlap each other, and the average energy of each state of the arrangement [Ar] 4s1 3d9 is lower than that of [Ar] 4s2 3d8. Therefore, the research literature of atomic calculation cites [Ar] 4s1 3d9 for the ground state arrangement of nickel.

　　Use

At present, the proportion of nickel use in the United States is as follows: 46% is used to produce nickel steel, 34% is used to produce non-ferrous alloys and superalloys, 14% is used for electroplating, and the remaining 6% is used for other purposes.

Nickel is used in a variety of specific and easily recognizable industrial and consumer products, including stainless steel, Alnico magnets, coins, batteries, guitar strings, microphone boxes and a variety of special alloys. In particular, it should be emphasized that nickel is an alloy metal, and its main use is nickel steel and nickel cast iron, and there are many kinds of them. Nickel is also widely used in other alloys, such as nickel brass and nickel bronze, and other alloys containing various metal elements (such as high-nickel, high-alloy, monel alloy and nickel monk alloy), and various alloying elements include copper, chromium, aluminum, lead, cobalt, silver and gold.

Because nickel has good corrosion resistance, people in the past occasionally used nickel instead of silver for decoration. Beginning in 1859, some countries occasionally used nickel as a cheap coinage material (see above), but by the late 20th century nickel in coins had largely been replaced by cheaper stainless steel (I. e. iron), with the United States coin being an important exception to this trend.

For some precious metals, nickel is an excellent alloying agent, so nickel is used in the so-called fire assay method, specifically to detect various platinum elements. In this regard, nickel can detect all six elements from the ore of platinum elements, and even a little gold can be detected. High-flux nickel ore may also be engaged in the mining of other platinum group elements (mainly platinum and palladium). Examples of such mines are the Norilsk Basin in Russia and the Soderberry Basin in Canada.

Foam nickel and nickel mesh can be used for gas diffusion electrodes of alkaline fuel cells.

Nickel and its alloys are often used as catalysts for hydrogenation reactions. Raney nickel is a commonly used form of nickel catalyst, which is a nickel-aluminum alloy with a porous structure, but other catalysts, such as the related "Raney-type" catalysts, are often used.

Nickel is a natural magnetostrictive material, that is, the length of this material will change slightly under a magnetic field. In the case of nickel, the change in length is reduced (I. e., material shrinkage), also known as negative magnetostriction, and the degree of radiation is about 50 parts per million.

Nickel is also used for cemented tungsten carbide or other hard metal industrial products in amounts of about 6-12% by weight. Nickel can make tungsten carbide magnetic and provide corrosion resistance to sintered tungsten carbide parts, but its hardness is lower than that of cobalt for sintering.

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