So, today I want to tell you about the hardest metal on Earth – chromium. As usual, let’s first see where chromium is in the periodic table of chemical elements. Oh, there it is, hiding behind the vanadium in the 6th group.And yes, I did not deceive you, it is true that chromium has the highest hardness of all metals, based on the Mohs scale that shows the resistance of a mineral to scratching.
source/image: Thoisoi2 – Chemical Experiments!
Externally, pure chromium is a lustrous white metal that does not tarnish in air. To demonstrate the main feature of chromium, namely its topmost hardness, I will scratch an ordinary silicate glass with it.As you can see on this chart, the hardness of the glass is much smaller. As usual, you cannot fool physics, chromium easily scratched the surface of the glass, leaving a clearly discernible markings. Although, I think that the hardness of chromium is very much dependent on its purity.
Metallic chromium is obtained from the chromium ore mineral by reducing it using carbon to produce ferrochromium, an alloy of chromium and iron, which is used in production of stainless steel.We will now turn to the chemical properties of chromium which this metal is highly enriched with. The fact is, even the name of the metal, chromium, comes from the Greek “khroma” meaning color.
This name came to pass due the fact that chromium compounds can have almost all the colors of a rainbow. In a laboratory the most common chromium compound is potassium dichromate.It is used often in analytical chemistry, or to clean chemical dishes from the very stubborn dirt. Also, this substance is used as an intermediate compound in the production of chromium metal from ore./Thoisoi2 – Chemical Experiments!