
Solid metallic hydrogen has been produced in the laboratory - ars
https://arxiv.org/abs/1610.01634
======
twic
> We used type IIac conic synthetic diamonds (supplied by Almax Easy-Lab) with
> ~30 micron diameter culet flats. About 5 microns were etched off of the
> diamond culets using the technique of reactive ion etching, to remove
> defects from the surface. The diamonds were then vacuum annealed at high
> temperature to remove residual stress. Alumina is known to act as a
> diffusion barrier against hydrogen. The diamonds, with the mounted rhenium
> gasket, were coated with a 50 nm thick layer of amorphous alumina by the
> process of atomic layer deposition.

Incredible technology!

> The pressure was initially determined to ~88 GPa by ruby fluorescence using
> the scale of Chijioke et al (20); the exciting laser power was limited to a
> few mW. At higher pressures we measured the IR vibron absorption peaks of
> hydrogen with a Fourier transform infrared spectrometer with a thermal IR
> source, using the known pressure dependence of the IR vibron peaks for
> pressure determination (see SM).

Just incredible!

> Photos were taken with a smartphone camera at the ocular of a modified
> stereo microscope

...

~~~
NikhilVerma
> Photos were taken with a smartphone camera at the ocular of a modified
> stereo microscope

Still incredible! We as people tend to underestimate just how "magical" our
mobile phones are.

~~~
dr_zoidberg
Considering the expensive equipment and processes, it's a wonder why they
didn't use any scientific-grade CCD sensor.

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toufka
Super cool stuff! There are some greatly quotable sentences in the paper:

> Moreover, SMH (solid metal hydrogen) is predicted to be metastable so that
> it may exist at room temperature when the pressure is released. If so, and
> superconducting, it could have an important impact on mankind’s energy
> problems and would revolutionize rocketry as a powerful rocket propellant.

> The principal limitation for achieving the required pressures to observe SMH
> in a DAC (diamond anvil cell) has been failure of the diamonds.

> The sample was cryogenically loaded at 15 K and included a grain of ruby for
> pressure determination.

> As of the writing of this article we are maintaining the first sample of the
> first element in the form of solid metallic hydrogen at liquid nitrogen
> temperature in a cryostat.

~~~
mrfusion
If it's stable at room temperature wouldn't it make a really high density fuel
too?

~~~
dogma1138
Metallic Hydrogen can also be a liquid and even a gas, the metallic part
indicates it's an electric conductor, not a solid. The "idea" behind metallic
hydrogen is that since hydrogen is above the alkali metals in the periodic
tables there should be a phase where it behaves like a metal, the state of the
phase is not defined as a solid/gas/liquid in fact in all honesty it would
exist as all 3 and more.

The first production of metallic oxygen was a liquid, this is the first solid
one, tho at these pressures it's really unlikely that it would effective as
fuel store. One of the more interesting parts about metallic hydrogen is the
information we learn also applies to hydrides (hydrogen alloys) especially
things like Lithium-Hydrogen since basically you can stabilize a large amount
of hydrogen atoms (6 or more) around a single atom of Lithium, this might
actually be very interesting for a lot of applications including energy
storage. Hydrides should be considerably more stable and more importantly at
considerably lower pressures which would mean that they can actually be used
for various applications since you are not going to find something that only
can exist at 400 gPA levels of pressure or higher very useful for high stress
applications.

~~~
DenisM
Metallic hydrogen is atomic, recombining two atoms into an h2 molecule
releases huge amount of energy. Iirc 4x as much as burning h2 in oxygen.

~~~
dogma1138
Technically it's degenerate matter since the atoms do not interact due to the
pressure and other conditions, this happens because the electrons would have
to follow the exclusion principle under those pressures/densities the
electrons basically separate from the hydrogen proton as they cannot occupy
the same space and the hydrogen becomes a degenerate matter; a sea of
electrons flowing freely through a lattice of protons, because of this none of
the "atoms" can combine into molecules, but they aren't technically atoms at
that point either.

The problem with hydrogen as fuel storage (mainly for space travel) is the
pressure, operating a fuel tank at 400 gPA or higher is going to be tricky,
I've edited my previous post and added the bit about Hydrides which might
actually considerably more viable for both terrestrial and space applications.

If we can actually make LiH6 alloys and can find an easy way to break them
apart it can be a great fuel source, yes we might have to carry some "dead
weight" but Li has an atomic number of 3 Oxygen has an atomic number of 8,
considering that Hydrogen-Oxygen reaction is pretty much 1 to 1 (well "2") we
have to carry considerably more Oxygen now than we would have to carry
Lithium. If a Hydrogen-Hydrogen reaction could be harvested as a propellant it
would still be more effective than what we have even if we don't find any
clever ways of catalyzing the lithium we already carry to push the reaction
even further, we might be able to carry a smaller amount of oxygen also to
catalyze the lithium tho I'm not sure if the energy from that reaction would
be worth the added weight of the oxygen and the parts of the fuel and
propulsion systems that would support it and the O-Li process.

P.S.

Metallic hydrogen is also of "interest" to those who still study cold fusion,
even tho you can't call it cold fusion any more due to the stigma, at certain
conditions there is a high likelihood of Inertial Confinement Fusion and Pycno
Nuclear Fusion occurring, this often brought up as "superconductor fusion"
simply because you can't call anything cold fusion and get it published.

That might also be a quite interesting fuel source, especially if you simply
need to push it to a certain limit and once the fusion kicks in it would
transition to other fusion stages.

And lastly this might be especially interesting if we can make Li-Deuterium
alloys since D-Li fusion produces Helium 4 and over 20 MeV of energy :)

This (last) type of fusion is extremely interesting because not only it's
highly energetic but it's aneutronic, which means that less than 1% of the
energy is released via neutrons vs 80-90% in other forums of fusion,
aneutronic fusion produces tons of energy an pretty much no ionizing radiation
which means if you can make it work it would be in theory a safe enough
battery to power a cellphone without frying your brain.

~~~
ozzy6009
>The problem with hydrogen as fuel storage (mainly for space travel) is the
pressure, operating a fuel tank at 400 gPA or higher is going to be tricky

Operating a fuel tank at 1 MPa is tricky. Operating a fuel tank at 400 GPa is
ludicrous.

~~~
Avernar
So that's how Spaceball 1 could reach ludicrous speed. You learn something new
every day...

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npunt
Very exciting! For context, here's a nice long article (Aug 2016, 2 months
before this arxiv paper came out) on the recent history of attempts to make
it, with quotes from author of current paper and others in the field:

[https://www.sciencenews.org/article/pressure-make-
metallic-h...](https://www.sciencenews.org/article/pressure-make-metallic-
hydrogen)

> A few months later, Silvera’s group squeezed hydrogen hard enough to make it
> nearly opaque, though not reflective — not quite a metal. “We think we’re
> just below the pressure that you need to make metallic hydrogen,” Silvera
> says. His findings are consistent with Eremets’ new phase, but Silvera
> disputes Eremets’ speculations of metallicity. “Every time they see
> something change they call it metallic,” Silvera says. “But they don’t
> really have evidence of metallic hydrogen.”

> All this back and forth may seem chaotic, but it’s also a sign of a swiftly
> progressing field, the researchers say. “I think it’s very healthy
> competition,” Gregoryanz says. “When you realize that somebody is getting
> ahead of you, you work hard.”

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InDemoVeritas
I saw it! A tiny, shiny speck under the microscope, and the thrill of seeing a
form of matter which, it can be argued, has never existed anywhere in the
universe. Ever.

~~~
mmastrac
Would the pressures in a Jovian not be enough to form metallic hydrogen?

~~~
zeristor
By Jove?!

~~~
sho
Your attempt at humour has been rightly sanctioned, but you weren't all that
far from the mark. Jove is another name for the roman god Jupiter, and as such
a Jovian planet is one that resembles Jupiter - ie. large gas giants, where
metallic hydrogen is certainly thought to exist in nature.

Not by Jove - _inside_ Jove.

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resist_futility
Just for reference the pressure at the center of the Earth is estimated to be
around 360 GPa, while they are using 495 GPa and DACs able to reach over 700
GPa.

[https://en.wikipedia.org/wiki/Diamond_anvil_cell](https://en.wikipedia.org/wiki/Diamond_anvil_cell)

~~~
sixbrx
Jupiter, however is up to the task :)

Liquid Metallic hydrogen in Jupiter's core: [https://science.nasa.gov/science-
news/science-at-nasa/2011/0...](https://science.nasa.gov/science-news/science-
at-nasa/2011/09aug_juno3/)

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mrfusion
Guys, this is literally the holy grail of high pressure physics!

~~~
rspeer
What, like they made a cup out of it already?

~~~
LeoPanthera
"Now that is the cup of a high-pressure physicist."

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mrfusion
[https://en.m.wikipedia.org/wiki/Metallic_hydrogen](https://en.m.wikipedia.org/wiki/Metallic_hydrogen)

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fratlas
Someone with a chem/physics background, could you please explain why metallic
hydrogen is only theorized to be a superconductor? Is such a property not
predictable?

~~~
sidek
The problem (not having a condensed matter background, so my answer might not
be entirely right) is that we can't solve the Schrödinger equation exactly for
many-atom systems.

So we need to approximate our solutions to be able to get a good idea of what
properties a material will have. Our approximations are pretty good and we
have a decent idea of when some things superconductor. But our theories of
superconduction aren't yet perfect, and sometimes the approximations can
fail//generate behavior unexpected by our theories.

~~~
selimthegrim
In general, we can only predict ground state properties with accuracy.
Properly predicting high temperature superconductivity requires generating
information about the Fermi surface that is not just a matter of ground
states. If this is standard BCS model stuff then you might be able to get away
with some rules of thumb.

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simonhamp
495GPa... doesn't seem so bad...

Standard atmospheric pressure ~= 100Pa

So they increased the pressure in that chamber by 4.95billion times.

And then they hypothesise that the hydrogen metal could be stable at room
temperature.

Oh. My. Days.

~~~
davidhowlett
Standard atmospheric pressure is ~= 100kPa

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mrfusion
Did they test if it's super conducting?

~~~
michaelcampbell
Out of curiosity, what made you ask this? Is there something about Hydrogen
that would elicit such a question, or is that just a question that should be
asked of any new material?

As I said, I'm genuinely curious. I'm not even an amateur here, but I wouldn't
have thought to ask this at all.

~~~
rhubarbquid
Metallic hydrogen was theorized to be a superconductor in a 1968 paper:
[http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.21....](http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.21.1748)

