Most heavy metals are rare and extremely valuable. Many advances in modern technology and medicine would be impossible if they were not.
Most of these metals are not widely home use (at best, there comes to mind platinum and gold). Therefore, the value of many of them to civilization can only be judged by specialists. The story of the discovery of some quite interesting.
Here is the ranking of the densest metals in the world.
10. Tantalum — 16,67 g/cm3
Extremely refractory (the melting point of 3017 °C), tantalum in many cases successfully replaces platinum.
Used in jewelry — it is made from, the cases, bracelets and other jewelry. This contributes to the high hardness of the metal. In addition, it is cheaper than platinum, though more expensive silver.
His joints replace platinum as a catalyst in the chemical industry. In the glassmaking additive into the melt of this metal allows to obtain the glass used for the production of small binoculars and light points. And tantalum indispensable in the production of electronics.
9. Uranium — 19,05 g/cm3
On behalf of this item went the designation of the planets of the Solar system, and not Vice versa, as many believe.
This is a very hard, flexible and malleable metal. Able to spontaneously ignite. It is a lot like in the earth's crust and in seawater.
Thanks to the uranium in the end of IXX century, accidentally discovered invisible rays (known today as the phenomenon of emission of some natural substances of the invisible rays are called radioactive).
Natural uranium oxide from ancient times used in the manufacture of glazes for ceramic products. In our day compound of this metal are also used to create yellow paint.
8. Tungsten — 19,29 g/cm3
The absolute champion of refractoriness. Boils at a temperature of 5555 °C (the same in the photosphere of the Sun).
The word tungsten means "eats tin as a wolf." This name appeared not by chance. Tungsten, in the midst of tin ores, interfered with the smelting of tin.
Used to create wedding rings. Their durability represents the stability of personal relationships. Besides, polished tungsten does not scratch.
Used in the manufacture of filaments in different lighting.
7. Gold — 19,29 g/cm3
The content of gold in the ground is very low, although deposits rich in them, a lot. A little bit of gold is even in the water — in every cubic meter is present for at least five micrograms of gold.
Under normal conditions, is not oxidized and does not react with most acids, therefore is considered a noble metal.
Gold is easy to transmit heat and electricity, making indispensable in electronics.
6. Plutonium — 19,80 gr/cm3
The first artificial chemical element whose production is almost immediately after opening began on an industrial scale.
Named in honor of Pluto, which in 2006, "demoted", depriving of the status of the planet.
Interest in plutonium was initially caused by his military application. High density and anomalously high compressibility given the opportunity to produce compact, powerful and structurally simple atomic charges.
All plutonium isotopes are radioactive. "Reactor's" plutonium allows you to create a maintenance-free long-lived (up to one hundred years of operation) energy sources.
5. Neptunium — 20,47 g/cm3
Was derived artificially from uranium by nuclear reactions. Interestingly, not named after the Greek God Neptune, and indirectly — due to practical invisibility in nature in honor of the planet Neptune, which itself was named in honor of a deity, but a long time did not respond to the observation of astronomers.
It's metal self has no value, but in radiochemical industry is the "stepping stone" from Uranus to obtain the following important radio material — plutonium.
4. Rhenium — 21,01 g/cm3
Named after the river Rhine, at the place of opening.
Very rare, the only cost-effective rhenium Deposit is located in Russia.
Refractoriness, chemical neutrality and good ductility can also use this metal to create medical instruments.
Heat-resistant alloy of rhenium with other metals are used for the production of jet engines. Thus, the rhenium is of critical strategic military importance.
3. Platinum — 21,40 gr/cm3
The name platinum came up with the conquistadors. Literally in Spanish it means "serebristo". Explains such disparaging naming a special high-melting metal. For many years he did not know how to apply, then platinum was worth half the price of silver.
In our days is appreciated much more, even gold. The extreme refractoriness, chemical inertness and excellent properties of the catalyst of chemical reactions makes it indispensable in industry. The high cost and good durability open the way for use in jewelry.
2. Osmium — of 22.61 g/cm3
The name comes from the Greek "smell", as some chemical reaction with osmium selects the connection is very resistant bad "flavor."
In chemistry and industry as a catalyst. Durability and chemical neutrality make the metal indispensable in the manufacture of medical implants.
1. Iridium — 22,65 g/cm3
Salts of iridium in different variety of colors. The name of the metal comes from the name of iris, the Greek goddess of the rainbow.
In the crust of iridium in forty times less than gold. In meteorite substance its content much more than on Earth.
Combining the iridium with the platinum, you can get the alloy is extremely durable and chemically resistant.
Iridium is a great catalyst, but due to the rarity of this metal and high cost, its use is limited. However, car owners are familiar iridium spark plugs — they use the refractoriness and catalytic properties of a thin coating of iridium.