Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists discover helium chemistry

07.02.2017

An international team of researchers have predicted two stable helium compounds -- NaHe and NaHeO

Although helium is the second most-abundant element (after hydrogen) in the universe, it doesn't play well with others. It is a member of a family of seven elements called the noble gases, which are called that because of their chemical aloofness -- they don't easily form compounds with other elements. Helium, widely believed to be the most inert element, has no stable compounds under normal conditions.


Crystal structure of Na2He, resembling a three-dimensional checkerboard. The purple spheres represent sodium atoms, which are inside the green cubes that represent helium atoms. The red regions inside voids of the structure show areas where localized electron pairs reside.

Illustration is provided courtesy of Artem R. Oganov

Now, an international team of researchers led by Skoltech's Prof. Artem R. Oganov (also a professor at Stony Brook University and head of Computational Materials Discovery laboratory at Moscow Institute of Physics and Technology) has predicted two stable helium compounds -- Na2He and Na2HeO. The scientists experimentally confirmed and theoretically explained the stability of Na2He. This work could hold clues about the chemistry occurring inside gas giant planets and possibly even stars, where helium is a major component. The work is published by Nature Chemistry.

The authors of the study used a crystal structure-predicting tool, the first-principles evolutionary algorithm called USPEX, to conduct a systematic search for stable helium compounds. They predicted the existence of Na2He, which was then successfully synthesized in a diamond anvil cell (DAC) experiment performed at the Carnegie Institution for Science in Washington by Prof. Alexander F. Goncharov and his colleagues. The compound appeared at pressures of about 1.1 million times Earth's atmospheric pressure and is predicted to be stable at least up to 10 million times that.

... more about:
»Electrons »Helium »Na2He »Na2HeO »helium atoms »physics »sodium

"The compound that we discovered is very peculiar: helium atoms do not actually form any chemical bonds, yet their presence fundamentally changes chemical interactions between sodium atoms, forces electrons to localize inside cubic voids of the structure and makes this material insulating," says Xiao Dong, the first author of this work, who was a long-term visiting student in Oganov's laboratory at the time when this work was done.

Na2He is what's called an electride, which is a special type of an ionic salt-like crystal. It has a positively charged sublattice of sodium ions and another negatively charged sublattice formed of localized electron pairs. Because electrons are strongly localized, this material is an insulator, meaning that it cannot conduct the free-flowing electrons that make up an electric current.

The other predicted helium compound, Na2HeO, was found to be stable in the pressure range from 0.15 to 1.1 million atmospheres. It is also an ionic crystal with a structure similar to that of Na2He. However, in place of electron pairs, it has negatively charged oxygen in the form of O²?.

"This study shows how new surprising phenomena can be discovered by combination of powerful theoretical methods and state-of-the-art experiments. It shows that very weird chemical phenomena and compounds can emerge at extreme conditions, and the role of such phenomena inside planets needs to be explored," says Oganov.

Media Contact

Asya Shepunova
shepunova@phystech.edu
7-916-813-0267

 @phystech

https://mipt.ru/english/ 

Asya Shepunova | EurekAlert!

Further reports about: Electrons Helium Na2He Na2HeO helium atoms physics sodium

More articles from Life Sciences:

nachricht How molecules teeter in a laser field
18.01.2019 | Forschungsverbund Berlin

nachricht Discovery of enhanced bone growth could lead to new treatments for osteoporosis
18.01.2019 | University of California - Los Angeles

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Ten-year anniversary of the Neumayer Station III

The scientific and political community alike stress the importance of German Antarctic research

Joint Press Release from the BMBF and AWI

The Antarctic is a frigid continent south of the Antarctic Circle, where researchers are the only inhabitants. Despite the hostile conditions, here the Alfred...

Im Focus: Ultra ultrasound to transform new tech

World first experiments on sensor that may revolutionise everything from medical devices to unmanned vehicles

The new sensor - capable of detecting vibrations of living cells - may revolutionise everything from medical devices to unmanned vehicles.

Im Focus: Flying Optical Cats for Quantum Communication

Dead and alive at the same time? Researchers at the Max Planck Institute of Quantum Optics have implemented Erwin Schrödinger’s paradoxical gedanken experiment employing an entangled atom-light state.

In 1935 Erwin Schrödinger formulated a thought experiment designed to capture the paradoxical nature of quantum physics. The crucial element of this gedanken...

Im Focus: Nanocellulose for novel implants: Ears from the 3D-printer

Cellulose obtained from wood has amazing material properties. Empa researchers are now equipping the biodegradable material with additional functionalities to produce implants for cartilage diseases using 3D printing.

It all starts with an ear. Empa researcher Michael Hausmann removes the object shaped like a human ear from the 3D printer and explains:

Im Focus: Elucidating the Atomic Mechanism of Superlubricity

The phenomenon of so-called superlubricity is known, but so far the explanation at the atomic level has been missing: for example, how does extremely low friction occur in bearings? Researchers from the Fraunhofer Institutes IWM and IWS jointly deciphered a universal mechanism of superlubricity for certain diamond-like carbon layers in combination with organic lubricants. Based on this knowledge, it is now possible to formulate design rules for supra lubricating layer-lubricant combinations. The results are presented in an article in Nature Communications, volume 10.

One of the most important prerequisites for sustainable and environmentally friendly mobility is minimizing friction. Research and industry have been dedicated...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Our digital society in 2040

16.01.2019 | Event News

11th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Aachen, 3-4 April 2019

14.01.2019 | Event News

ICTM Conference 2019: Digitization emerges as an engineering trend for turbomachinery construction

12.12.2018 | Event News

 
Latest News

Additive manufacturing reflects fundamental metallurgical principles to create materials

18.01.2019 | Materials Sciences

How molecules teeter in a laser field

18.01.2019 | Life Sciences

The cytoskeleton of neurons has been found to be involved in Alzheimer's disease

18.01.2019 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>