Is metallic hydrogen superconductive at 273k

[ensabah6]

and if so is it the highest temperature superconductor known?

 

[f95toli]

No one has -as far as I know- ever even demonstrated that metallic hydrogen is a superconductor (all known phases are insulating). It is most definitely not a superconductor at 273K

(which is a bit of a "silly" temperature anyway, it happens to be equal to 0 degrees Celsius which is also the freezing temperature of water; it would if nothing else be a HUGE coincidence if metallic H had a Tc of that temperature).

 

[Orion1]

Superconductivity:

In 1968, Ashcroft put forward that metallic hydrogen may be a superconductor, up to room temperature (~290 K), far higher than any other known candidate material. This stems from its extremely high speed of sound and the expected strong coupling between the conduction electrons and the lattice vibrations.

...The team had sought simply to measure the less extreme electrical conductivity changes which were expected to occur. The researchers used a 1960s-era light gas gun, originally employed in guided missile studies, to shoot an impactor plate into a sealed container containing a half-millimeter thick sample of liquid hydrogen. The liquid hydrogen was in contact with wires leading to a device measuring electrical resistance. The scientists found that, as pressure rose to 1.4E+6 atm (142 GPa), the electronic energy band gap, a measure of electrical resistance, fell to almost zero.

Reference:
http://en.wikipedia.org/wiki/Metallic_hydrogen#Superconductivity"

 

[f95toli]

Yes, metallic hydrogen has been predicted to be superconducting at very high temperatures. But no one has actually shown that this prediction is correct.
Also, the pressure needed to keep the hydrogen metallic at 290K would be truly enormous.