Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Mainz scientists confirm original tetrahedral model of the molecular structure of water

Resolution of controversy about structure of liquid water

Researchers at Johannes Gutenberg University Mainz (JGU) have confirmed the original model of the molecular structure of water and have thus made it possible to resolve a long-standing scientific controversy about the structure of liquid water.

Model of a symmetrical four bond water molecule (oxygen red and hydrogen white)

ill./©: Thomas D. Kühne

The tetrahedral model was first postulated nearly 100 years ago and it assumes that every water molecule forms a so-called hydrogen bond with four adjacent molecules. This concept was almost toppled in 2004 when an international research group announced that it had experimentally established that water molecules form bonds only with two other molecules.

"The quality of the results was excellent but they merely represent a snapshot of the situation," explained Professor Dr. Thomas Kühne. He has demonstrated the fallacy of the 'double bonding' theory using computer simulations based on new types of combinations of two computational methods recently developed by his group.

Some very special and unique features of water, such as its liquid aggregate state and high boiling point, are attributable to the effect of the hydrogen bonds between the water molecules. The H bonds are formed due to the different charges carried by the oxygen and hydrogen atoms that make up water molecules and the resultant dipolar structure. The traditional, generally accepted view was that water had a tetrahedral structure at room temperature, so that on average each water molecule would be linked with four adjacent molecules via two donor and two acceptor bonds. "In our theoretical approach, the median result we observed over time was always for quadruple bonding," said Kühne. Thanks to the new simulations, he and his colleague Dr. Rhustam Khaliullin have now been able to confirm the old model and also supply an explanation for why double bonding was observed in 2004. According to Kühne, the result was not indicative of double bonding "but of instantaneous asymmetrical fluctuation" only.

There is thus significant asymmetry in the four H bonds of the tetrahedral model because of the different energy of the contacts. This asymmetry is the result of temporary disruptions to the hydrogen bond network, which take the form of extremely short term fluctuations occurring on a timescale of 100 to 200 femtoseconds. These fluctuations mean that one of the two donor or acceptor bonds is temporarily much stronger than the other. But these fluctuations precisely cancel each other out so that, on average over time, the tetrahedral structure is retained.

The results reported in 2004 using x-ray absorption spectroscopy were obtained using water molecules with high levels of momentary asymmetry, which is why essentially only two strong hydrogen bonds were observed in an otherwise tetrahedral structure. "Our findings have important implications as they help reconcile the symmetric and asymmetric views on the structure of water," write the scientists in an article published in Nature Communications. The results may also be relevant to research into molecular and biological systems in aqueous solutions and provide insight into protein folding, for example.

The work of Thomas Kühne's group was undertaken within an interdisciplinary joint project and was funded by the Research Unit Center for Computational Sciences at Johannes Gutenberg University Mainz.

Thomas D. Kühne, Rustam Z. Khaliullin
Electronic signature of the instantaneous asymmetry in the first coordination shell of liquid water
Nature Communications, February 2013

Further information:
Junior Professor Dr. Thomas D. Kühne
Institute of Physical Chemistry
Research Unit Center for Computational Sciences
Johannes Gutenberg University Mainz
D 55099 Mainz, GERMANY
phone +49 6131 39-23699

Petra Giegerich | idw
Further information:

More articles from Life Sciences:

nachricht Novel mechanisms of action discovered for the skin cancer medication Imiquimod
21.10.2016 | Technische Universität München

nachricht Second research flight into zero gravity
21.10.2016 | Universität Zürich

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>