Tungsten – The Most Refractory Metal On Earth

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Tungsten is one of the transition metals, and is located in group 6 of the periodic table of chemical elements.It got it’s name from the mineral wolframite, from which this mineral is obtained. Also, a tiny fun fact, wolfram is a Swedish word.Now if we look at the appearance, tungsten looks like a shiny metal with gray tint, though if you hold a rod of tungsten in the hand you may experience one special characteristic.

image/text credit: Thoisoi2

The density of tungsten is almost 20 grams per cubic centimeter, which is very close to the density of gold.That is the reason why tungsten was used for faking gold bars. A couple of years ago there was news that some gold bars had a filling of tungsten inside, which of course is significantly cheaper than gold.

image/text credit: Thoisoi2

Though the forgery causes skepticism among some scientists. To clearly demonstrate to you how much is 20 gram per cubic centimeter, I will compare the mass of a rod of tungsten and a rod of magnesium.As you can see, the tungsten rod is not only several times smaller than the magnesium one, but is also even heavier than the latter.

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Also, tungsten is a fairly brittle metal, it is plastic only when it has a very high purity. In addition, tungsten has the highest tensile strength.However, this is not the main feature of this metal. To melt a piece of tungsten, you need to reach an extremely high temperature of 3422 degrees Celsius.That is why this metal was at first used as the filament in incandescent bulbs.

However, if you pass a current through the thin tungsten filament, it can overheat and then break, thereby ceasing any production of light .All is due to the fact that in air tungsten oxidizes at a high temperature, forming on its surface oxides of tungsten.Also, the tungsten rod after calcination with a gas burner obtains beautiful colored stains, caused by the different thickness of the oxide film on the metal surface.