Nav: Home

Unusual electron sharing found in cool crystal

July 31, 2020

A team of scientists led by Nagoya University in Japan has detected a highly unusual atomic configuration in a tungsten-based material. Until now, the atomic configuration had only been seen in trihydrogen, an ion that exists in between star systems in space. The findings, published in the journal Nature Communications, suggest further studies could reveal compounds with interesting electronic properties.

Atoms that make up humans and trees and kitchen tables generally bond together by sharing electrons - think of electrons as the atomic glue of life. Nagoya University applied physicist Yoshihiko Okamoto and colleagues have found a highly unusual version of this glue: a regular triangular molecule was formed of three atoms bonded together by two electrons.

"This type of bond had only previously been seen in the trihydrogen ions found in interstellar material," says Okamoto. "We were excited to see this configuration in a cooled tungsten-based crystal."

The so-called tritungsten molecules were discovered in single crystals of caesium tungsten oxide (CsW2O6) cooled below -58°C. CsW2O6 conducts electricity at room temperature but changes into an insulating material when it is cooled below -58°C. It has been a challenge to study how the atomic structure of this type of material changes in response to temperature. To overcome this, Okamoto and his colleagues in Japan synthesized very pure single crystals of CsW2O6 and bombarded them with X-ray beams at room temperature and -58°C.

The tungsten molecules in the conducting crystal form three-dimensional networks of tetrahedral pyramids connected at their corners, known as a pyrochlore structure. The bonds between the molecules form due to a symmetrical sharing of electrons between them.

However, when the compound is cooled, the electrons re-arrange and two types of tungsten atoms emerge within the tetrahedra, each with a different 'valence', or bonding power with other atoms. This, in turn, distorts the lengths of tungsten bonds with oxygen atoms in the compound, leading to a more compressed shape. Importantly, the tungsten atoms with lower valence form small and large triangles on the sides of the tungsten tetrahedra, with the highly unusual tritungsten molecules forming on the small triangles. The three tungsten atoms forming the points of these triangles share only two electrons between them to keep them bonded together.

"To our knowledge, CsW2O6 is the only example where this type of bond formation, where several atoms share only a few electrons, appears as a phase transition," says Okamoto.

The team aims to further investigate compounds with pyrochlore structures, with the ultimate goal of discovering materials with new and interesting properties.
-end-
The paper, "Regular-triangle trimer and charge order preserving the Anderson condition in the pyrochlore structure of CsW2O6," has been published in the journal Nature Communications at DOI: 10.1038/s41467-020-16873-7.

Contact: Yoshihiko Okamoto
Graduate School of Engineering, Nagoya University
Email: yokamoto@nuap.nagoya-u.ac.jp

Nagoya University

Related Electrons Articles:

Self-imaging of a molecule by its own electrons
Researchers at the Max Born Institute (MBI) have shown that high-resolution movies of molecular dynamics can be recorded using electrons ejected from the molecule by an intense laser field.
Electrons in the fast lane
Microscopic structures could further improve perovskite solar cells
Laser takes pictures of electrons in crystals
Microscopes of visible light allow to see tiny objects as living cells and their interior.
Plasma electrons can be used to produce metallic films
Computers, mobile phones and all other electronic devices contain thousands of transistors, linked together by thin films of metal.
Flatter graphene, faster electrons
Scientists from the Swiss Nanoscience Institute and the Department of Physics at the University of Basel developed a technique to flatten corrugations in graphene layers.
Researchers develop one-way street for electrons
The work has shown that these electron ratchets create geometric diodes that operate at room temperature and may unlock unprecedented abilities in the illusive terahertz regime.
Photons and electrons one on one
The dynamics of electrons changes ever so slightly on each interaction with a photon.
Using light to put a twist on electrons
Method with polarized light can create and measure nonsymmetrical states in a layered material.
What if we could teach photons to behave like electrons?
The researchers tricked photons - which are intrinsically non-magnetic - into behaving like charged electrons.
Electrons in rapid motion
Researchers observe quantum interferences in real-time using a new extreme ultra-violet light spectroscopy technique.
More Electrons News and Electrons Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Sound And Silence
Sound surrounds us, from cacophony even to silence. But depending on how we hear, the world can be a different auditory experience for each of us. This hour, TED speakers explore the science of sound. Guests on the show include NPR All Things Considered host Mary Louise Kelly, neuroscientist Jim Hudspeth, writer Rebecca Knill, and sound designer Dallas Taylor.
Now Playing: Science for the People

#576 Science Communication in Creative Places
When you think of science communication, you might think of TED talks or museum talks or video talks, or... people giving lectures. It's a lot of people talking. But there's more to sci comm than that. This week host Bethany Brookshire talks to three people who have looked at science communication in places you might not expect it. We'll speak with Mauna Dasari, a graduate student at Notre Dame, about making mammals into a March Madness match. We'll talk with Sarah Garner, director of the Pathologists Assistant Program at Tulane University School of Medicine, who takes pathology instruction out of...
Now Playing: Radiolab

Kittens Kick The Giggly Blue Robot All Summer
With the recent passing of Ruth Bader Ginsburg, there's been a lot of debate about how much power the Supreme Court should really have. We think of the Supreme Court justices as all-powerful beings, issuing momentous rulings from on high. But they haven't always been so, you know, supreme. On this episode, we go all the way back to the case that, in a lot of ways, started it all.  Support Radiolab by becoming a member today at Radiolab.org/donate.