Baron Axel Fredrik Cronstedt was a Swedish mineralogist and chemist who discovered the element nickel in 1751 as a mining expert with the Bureau of Mines.
Cronstedt is considered a founder of modern mineralogy, for introducing the blowpipe as a tool for mineralogists, and for proposing that the mineral kingdom be organized on the basis of chemical analysis in his book Försök til mineralogie, eller mineral-rikets upställning.
Axel Fredrik Cronstedt
Kit for blowpipe analysis Carl Osterland, Freiberg, c. 1870
Scheelite
Mine building at Los
Nickel is a chemical element; it has symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive, but large pieces are slow to react with air under standard conditions because a passivation layer of nickel oxide forms on the surface that prevents further corrosion. Even so, pure native nickel is found in Earth's crust only in tiny amounts, usually in ultramafic rocks, and in the interiors of larger nickel–iron meteorites that were not exposed to oxygen when outside Earth's atmosphere.
Nickel
Electron micrograph of a Ni nanocrystal inside a single wall carbon nanotube; scale bar 5 nm
Widmanstätten pattern showing the two forms of nickel–iron, kamacite and taenite, in an octahedrite meteorite
Color of various Ni(II) complexes in aqueous solution. From left to right, [Ni(NH3)6]2+, [Ni(NH2CH2CH2NH2)]2+, [NiCl4]2−, [Ni(H2O)6]2+