Iridium – The MOST RARE Metal on Earth!


[ATTENTION! This video shows dangerous experiments! Do not repeat the experiments shown in this VIDEO!] Hello everyone! Today I’ll tell you about the most rare metal on earth – iridium. Iridium is a transition metal, which is located in the middle of the periodic table, below rhodium. If we take a look at the abundance of all elements in the Earth’s crust, iridium holds the last place. That is a billion atoms of all that there is only one atom of iridium. This metal is 40 times rarer than gold. In much higher concentrations, iridium is found in meteorites and also in the depths of the earth, in magma. Interestingly enough, in the layers of rock sediments, though more precisely in the formation of clay that is aged about 66 million years, there were found high concentrations of iridium, and this can indicate the collision of Earth with a huge meteorite in the past, which in theory was the cause of the death of the dinosaurs. In its appearance, iridium is a shiny metal that does not oxidize in air. This metal has almost the highest density of all metals—just 0.12% lower that that of osmium, the most dense metal. In this tiny metal droplet which is of the size of a match head, we have one gram of iridium. To help you understand how high
is the density of iridium, I’ll show [Ir 22.56 g/cm³]
other metals with the same mass for comparison. Lead
[Pb 11.35 g/cm³] Copper
[Cu 8.96 g/cm³] Gallium
[Ga 5.91 g/cm³] Zinc
[Zn 7.13 g/cm³] Beryllium
[Be 1.85 g/cm³] Magnesium
[Mg 1.74 g/cm³] and the lightest metal—Lithium
[Li 0.53 g/cm³] The volumes of the first and the last metal differ [mass=1 gram]
by about 30 times, although their mass is the same. Iridium is also a very hard metal, that is harder than this solid steel by 1.5×. Iridium, in addition to its rarity, is even the most stable metal that does not oxidize in air up to 2,000 degrees, and is not soluble in either acid or aqua regia. Iridium can only react with fluorine, at temperatures about 600 degrees Celsius. Unfortunately, due to the low activity of iridium I cannot conduct any chemical experiments or have quality reactions with it. The only thing that I can do
is make a fine powder of iridium and set it on fire in the air. But as you can see, in this case iridium dust is burning quite slowly and also requires dispersing it in the air. For the first time on YouTube,
you can observe a burning iridium. Also, iridium compounds can be either brown or yellow, such as a complex of Vaska, which is used as a catalyst in organic chemistry. Due to the low activity of iridium, the metal does not tarnish in air even when heated to about 1,000 degrees Celsius. The only thing that a drop of iridium got covered with is a partially evaporated ceramic layer that the forceps are made from. By the way, iridium is the only element that can give away nine electrons and form compounds with +9 oxidation state. In most cases we will probably find iridium in spark plugs due to the high stability of iridium to oxidation under the influence of electric discharge. Pure iridium is useful making crucibles for growing single crystals, foil for making non-amalgamic cathodes, as well as a part of the highly resistant to corrosion alloys. The first standard of mass of one kilogram was created in 1889 using an alloy composition of ninety percent platinum and ten percent iridium and is still kept in the
Paris Bureau of Weights and Measures. By the way, for the fans who like counting numbers, one gram of iridium costs eighty dollars. For the provided iridium for the experiments, I would like to thank the company novaelements.com. This company is selling elements on eBay
to collectors around the world. Now you know more about one of the elements. If you would like the scientific series of the elements to continue, please subscribe to my channel, and also visit the homepage of my sponsor novaelements.com. Thank you for watching.

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