Controversial Science: Metallic Hydrogen

For many years it has been thought that hydrogen exists in a metallic form under significant pressure, however it has never been proven. This week a study was published by two German scientists in Nature Materials, a reputable peer-reviewed journal, indicating that they have discovered metallic hydrogen. Excitement has surrounded this material for years because of the plethora of possibilities for real world applications, however skepticism surrounds this discovery.

The experiment was performed by Mikhail Eremets and Ivan Troyan of the Max-Planck Institute for Chemistry in Mainz, Germany. They put 99.95% pure hydrogen into a diamond anvil cell. The device leaves room for a sample between two opposing diamonds and is used for experiments that need to be performed under extreme pressure, ~3,000,000 atmospheres (300 Gigapascals). Pressure, electric, and vibrational measurements were taken at low temperatures to examine the results.

Eremets and Troyan determined that at 220GPa and room temperature hydrogen exhibits electrically conductive activity. Then after lowering the temperature further and increasing the pressure they viewed metallic like behavior from the hydrogen, however the indication was subtle. Eremets and Troyan fully believe this is a sign of metallicity, but many other groups are not convinced by their evidence. Arthur Ruoff, a materials scientist at Cornell University and a leader in the search for metallic hydrogen, believes that there should be a 4000% resistance increase, but only a 20% resistance increase was seen by Eremets and Troyan.

Ruoff is not the only leader in the field with concerns about the bold claim. William Nellis at Harvard University expresses some of the same skepticism as Ruoff. They both think there could be an additional reaction happening with a material in the experimental apparatus.

Despite the controversy swirling around the recent publication, if or when metallic hydrogen is discovered it could lead to real world applications in the area of superconductivity. Perhaps, it is a little too early to get excited about this discovery, but the advancement in this area of materials science is something to be watchful over.

I have always been fascinated with the intersection of science and skepticism. If there is a controversial scientific debate you have always wondered about, please let me know. Perhaps after digging through the scientific literature, I can clear up some curiosities (or I can muck them up). Find me on twitter at jhargis9.


Jacqueline, a true Floridian, wandered up to the tundra of Athens, Georgia to receive her PhD in computational quantum chemistry. Returning to her roots, she is currently working as a postdoctoral researcher in Tampa in the field of computational biochemistry investigating the wonders of penicillin-like drugs. When she is not slaving over the computer, her varied interests include international travel, Brazilian jiu jitsu, kickboxing, fancy food, (American) football, and Belgian quadrupels. She is also the founder of, a football blog with an exclusive female writing staff. Check out her sports ramblings there or follow her on Twitter @jhargis9.

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  1. Wow, this takes me back! I did diamond anvil cell experiments for my doctoral work, although nowhere near these kinds of pressures. High enough, however, to demonstrate (to my advisor’s displeasure) that diamonds are NOT forever!

    I seem to recall seeing reports like this years ago, with similar attendant skepticism. I guess I’d agree with Ruoff that the resistance change they saw is not large enough. Given how long some of these folks have been chasing metallic hydrogen, the evidence is going to have to be pretty damn compelling for it not to provoke raised eyebrows.

    What I’m most skeptical about is any potential impact on real world applications. It’s really hard to imagine how this (whenever it finally gets confirmed) will lead to any advancements in practical superconductivity.

    1. That is awesome that you did diamond anvil cell experiments in grad school. To be honest, I hadn’t heard of them until I read this article. However, being a computational scientist I am poorly informed about some experimental techniques.

      I tend to get a little too excited when thinking about the real world applications of superconductors. The science is still pretty far away from obtaining room temperature superconductors which will ultimately be a huge breakthrough (and I suspect a Nobel prize). However, years from now when the science is nailed down there could be some real world applications depending on the cost of the materials.

      1. High pressure experiments are a fairly esoteric realm, so you can be excused for not having heard of them. Especially as a computational scientist! Even most experimental physics types have never heard of them.

        All in all, probably not the best choice of specialization for someone who wanted to be in commercial R&D. Thus the 4 years of post-doctoral work to show that I could actually do something useful!

    2. I’m skeptical too. This might teach us some interesting physics/chemistry, but I see no practical use for metallic hydrogen. The physicists I’ve asked about it say it’s mostly about testing the models for the way we think atoms should behave.

    1. You can buy Diamond Anvil Cells from Acme? Mail order? What’s the shipping like?

      In other silly jokes, has anyone notified Phil Plait? Astronomers regard the universe as consisting of hydrogen, helium and metals. This metallic hydrogen thing could Overturn Our Theory of the Universe As We Know It, leaving just helium and metals. (Yes, I know that many astronomers think the core of Jupiter (and maybe the other gas giant planets) is composed largely of metallic hydrogen.

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