Today's element is chromium, the first of the group 6 transition metals. It is denoted by the symbol Cr and atomic number 24. Chromium is a grey coloured, hard and very lustrous metal.
Chromium is highly corrosion resistant, a character that it brings with it when added to steel to create stainless steel. Another popular use for chromium is electroplating, which gave hubcaps, bumpers and other shiny bits of cars their bad-ass shiney-ness back in the late Cretaceous.
My favourite aspect of chromium is the intense colours of the various chromium(III) and chromium(VI) compounds. In fact, its name is derived from the Greek "chrōma" meaning colour, because many of its compounds are so intensely coloured. Besides providing the familiar non-fading "chrome yellow" colour used on American school buses and by the German postal service, there is the bright red pigment, chrome red (PbCrO4·Pb(OH)2), a bright green (Cr2O3), a pale green ([CrCl(H2O)5]Cl2), and rich violet ([Cr(H2O)6]Cl3). Trace amounts of chromium also gives rubies and emeralds their characteristic colours.
Pictured below is the lovely and relatively rare mineral, crocoite (PbCrO4), the state mineral of Tasmania.
Video journalist Brady Haran is the man with the camera and the University of Nottingham is the place with the scientists. You can follow Brady on twitter @periodicvideos and the University of Nottingham on twitter @UniNottingham
You've already met these elements:
Vanadium: V, atomic number 23
Titanium: Ti, atomic number 22
Scandium: Sc, atomic number 21
Calcium: Ca, atomic number 20
Potassium: K, atomic number 19
Argon: Ar, atomic number 18
Chlorine: Cl, atomic number 17
Sulfur: S, atomic number 16
Phosphorus: P, atomic number 15
Silicon: Si, atomic number 14
Aluminium: Al, atomic number 13
Magnesium: Mg, atomic number 12
Sodium: Na, atomic number 11
Neon: Ne, atomic number 10
Fluorine: F, atomic number 9
Oxygen: O, atomic number 8
Nitrogen: N, atomic number 7
Carbon: C, atomic number 6
Boron: B, atomic number 5
Beryllium: Be, atomic number 4
Lithium: Li, atomic number 3
Helium: He, atomic number 2
Hydrogen: H, atomic number 1
Here's a wonderful interactive Periodic Table of the Elements that is just really really fun to play with!
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