Hydrogen turned into a metal !

The Hydrogen Atom

One drawback of the Mendeleyev's periodic table existed till the 21st century in the modern periodic table- the contradictory position of Hydrogen in the alkali family in spite of being a non-metal.Many have tried but none have succeeded so far.
For more than a hundred yrs now scientists have been scratching their skin being mused over the fact that it is an alkali metal and should be a metal under normal circumstances but till today no one has been able to find out those normal conditions.

Mikhail Eremets and Ivan Troyan of the Max-Planck University explain how they increased the temperature and lowered the pressure of a Sample of Hydrogen and how Hydrogen showed the properties which were allotted only to metals in their paper published in Nature Materials.

The actual properties to say whether a material is metal or not is the simple property list of metals. Most books and encyclopedias describe a metal as an electropositive element, shiny, malleable to an extent, and good conductor of both heat and electricity and our common sense says that it should be a solid at some temperature and pressure.

They claim that when they did put a sample of Hydrogen in an alumina-epoxy gasket which they put inside a diamond anvil, an arrangement that helped in measuring the opacity via laser and the electrical resistance using electrodes, they found that without increasing or decreases the temperature and at a constant pressure of 220GPa, the sample started showing the property of being opaque and also started conducting electricity. Next the temperature was lowered to 30 Kelvin and increased the pressure to 260 GPa and found the electrical resistance increase of 20 % before it leveled off.

Deuterium

Abstract description:

"Hydrogen molecules are expected to exhibit metallic properties under mega bar pressure. This metallic body formed is predicted to be a superconductor at a very high critical temperature of 200-400 Kelvin and it may also acquire new Quantum state as a superconducting super fluid and a metallic super fluid.

It may be potentially recovered at ambient pressure. However experiments conducted at lower temperatures, i.e. less than 100 K showed that at a record pressure of 300 GPA, hydrogen remains in the insulating state.

Here we report on the transformation of normal molecular hydrogen at room temperature (295K) to a conductive and metallic state. At 200 GPa the Raman frequency of the molecular vibron strongly decreased and the phantom width increased, evidencing a strong interaction between molecules. Deuterium behaved similarly. Above 220 GPa, hydrogen became opaque and electrically conductive. At 260–270 GPa, hydrogen transformed into a metal as the conductance of hydrogen sharply increased and changed little on further pressurizing up to 300 GPa or cooling to at least 30 K; and the sample reflected light well. The metallic phase transformed back at 295 K into molecular hydrogen at 200 GPa. This significant hysteresis indicates that the transformation of molecular hydrogen into a metal is accompanied by a first-order structural transition presumably into a monatomic liquid state. Our findings open an avenue for detailed and comprehensive studies of metallic hydrogen."

So, by this the position of Hydrogen in the periodic table is justified and proved experimentally.

[Source : physorg.com]

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