Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Core electron topologies in chemical bonding

13.06.2018

Previously nodeless core electrons form nodes in unsaturated organic compounds

YNU researchers resolve the age-old mystery of why silicon cannot replace carbon in organic compounds. A new benchmark quantum chemical calculation of C2, Si2, and their hydrides for the first time reveals a qualitative difference in the topologies of core electron orbitals of organic molecules and their silicon analogues. Other elements with a similar propensity as carbon to reshape their core electron nodal structures upon chemical bonding are proposed.


Inner core electrons are expected to have a peanut like wavefunction as is shown for Si2s electrons (right). In the C-C bond, however, the C1s electrons form a torus like feature of opposite polarity, shown in pink in left figure.

Credit: Yokohama National University

Since the discovery of silicon and Wöhler's success in cheating nature by synthesizing organic compounds, Wöhler himself was among the first (in mid-19th century) to suggest replacing carbon by silicon in organic compounds. It became clear in the early 20th century that silicon does not have a chemistry similar to carbon, and dreams of silicon-based life only survive in science fiction.

We know empirically that carbon has the capability to form a variety of unsaturated compounds, which silicon has not. However, the root cause of why only carbon has such capability has remained a mystery.

Quantum chemical calculations of unprecedented accuracy carried out at YNU reveal that core electrons (which were not supposed to participate in chemical bonding) have a very different role in the unsaturated compounds of carbon and silicon.

Carbon has the propensity to alter the topology (nodal structure) of its core electrons, which for C2 results to the formation of a torus like ring in the 1σg orbital formed of C1s electrons (see Figure). Si2, however, maintains the spherical like core orbitals centered at each atomic site in all its molecules. This flexibility of carbon's core orbitals allows carbon to form a cornucopia of different valence bond structures, whereas silicon is restricted to bond structures orthogonal to the atomic like spherical core orbitals.

The impact of this discovery can be far reaching. Core electrons have thus far been assumed more or less inert, but perhaps it becomes necessary to reassess their contribution to chemical bonding -- at least in the case of unsaturated bonds. Finally, it is suggested that other elements, such as nitrogen, phosphorous, and fluorine, exhibit similar flexibility to modify their core electron topologies, and thus, exhibit similarly rich chemistries.

###

The paper "Core Electron Topologies in Chemical Compounds: Case Study of Carbon versus Silicon" is published in Angewandte Chemie International Edition vol 57(24) on June 6th, 2018, doi: 10.1002/anie.201713108

Yokohama National University (YNU or Yokokoku) is a Japanese national university founded in 1949. YNU provides students with a practical education utilizing the wide expertise of its faculty and facilitates engagement with the global community. YNU's strength in the academic research of practical application sciences leads to high-impact publications and contributes to international scientific research and the global society. For more information, please see: http://www.ynu.ac.jp/english

Akiko Tsumura | EurekAlert!
Further information:
http://dx.doi.org/10.1002/anie.201713108

More articles from Life Sciences:

nachricht CUHK Faculty of Engineering develops novel imaging approach
21.11.2019 | The Chinese University of Hong Kong

nachricht Machine learning microscope adapts lighting to improve diagnosis
20.11.2019 | Duke University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Small particles, big effects: How graphene nanoparticles improve the resolution of microscopes

Conventional light microscopes cannot distinguish structures when they are separated by a distance smaller than, roughly, the wavelength of light. Superresolution microscopy, developed since the 1980s, lifts this limitation, using fluorescent moieties. Scientists at the Max Planck Institute for Polymer Research have now discovered that graphene nano-molecules can be used to improve this microscopy technique. These graphene nano-molecules offer a number of substantial advantages over the materials previously used, making superresolution microscopy even more versatile.

Microscopy is an important investigation method, in physics, biology, medicine, and many other sciences. However, it has one disadvantage: its resolution is...

Im Focus: Atoms don't like jumping rope

Nanooptical traps are a promising building block for quantum technologies. Austrian and German scientists have now removed an important obstacle to their practical use. They were able to show that a special form of mechanical vibration heats trapped particles in a very short time and knocks them out of the trap.

By controlling individual atoms, quantum properties can be investigated and made usable for technological applications. For about ten years, physicists have...

Im Focus: Images from NJIT's big bear solar observatory peel away layers of a stellar mystery

An international team of scientists, including three researchers from New Jersey Institute of Technology (NJIT), has shed new light on one of the central mysteries of solar physics: how energy from the Sun is transferred to the star's upper atmosphere, heating it to 1 million degrees Fahrenheit and higher in some regions, temperatures that are vastly hotter than the Sun's surface.

With new images from NJIT's Big Bear Solar Observatory (BBSO), the researchers have revealed in groundbreaking, granular detail what appears to be a likely...

Im Focus: New opportunities in additive manufacturing presented

Fraunhofer IFAM Dresden demonstrates manufacturing of copper components

The Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM in Dresden has succeeded in using Selective Electron Beam Melting (SEBM) to...

Im Focus: New Pitt research finds carbon nanotubes show a love/hate relationship with water

Carbon nanotubes (CNTs) are valuable for a wide variety of applications. Made of graphene sheets rolled into tubes 10,000 times smaller than a human hair, CNTs have an exceptional strength-to-mass ratio and excellent thermal and electrical properties. These features make them ideal for a range of applications, including supercapacitors, interconnects, adhesives, particle trapping and structural color.

New research reveals even more potential for CNTs: as a coating, they can both repel and hold water in place, a useful property for applications like printing,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

First International Conference on Agrophotovoltaics in August 2020

15.11.2019 | Event News

Laser Symposium on Electromobility in Aachen: trends for the mobility revolution

15.11.2019 | Event News

High entropy alloys for hot turbines and tireless metal-forming presses

05.11.2019 | Event News

 
Latest News

The neocortex is critical for learning and memory

20.11.2019 | Life Sciences

4D imaging with liquid crystal microlenses

20.11.2019 | Physics and Astronomy

Walking Changes Vision

20.11.2019 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>