Featured Research

from universities, journals, and other organizations

Scientists confirm original tetrahedral model of molecular structure of water

Date:
February 11, 2013
Source:
Universität Mainz
Summary:
Researchers 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. 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.

Model of a symmetrical four bond water molecule (oxygen red and hydrogen white).
Credit: © Thomas D. Kühne

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. 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.

Related Articles


"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.


Story Source:

The above story is based on materials provided by Universität Mainz. Note: Materials may be edited for content and length.


Journal Reference:

  1. Thomas D. Kühne, Rustam Z. Khaliullin. Electronic signature of the instantaneous asymmetry in the first coordination shell of liquid water. Nature Communications, 2013; 4: 1450 DOI: 10.1038/ncomms2459

Cite This Page:

Universität Mainz. "Scientists confirm original tetrahedral model of molecular structure of water." ScienceDaily. ScienceDaily, 11 February 2013. <www.sciencedaily.com/releases/2013/02/130211202018.htm>.
Universität Mainz. (2013, February 11). Scientists confirm original tetrahedral model of molecular structure of water. ScienceDaily. Retrieved November 26, 2014 from www.sciencedaily.com/releases/2013/02/130211202018.htm
Universität Mainz. "Scientists confirm original tetrahedral model of molecular structure of water." ScienceDaily. www.sciencedaily.com/releases/2013/02/130211202018.htm (accessed November 26, 2014).

Share This


More From ScienceDaily



More Matter & Energy News

Wednesday, November 26, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

NASA's First 3-D Printer In Space Creates Its First Object

NASA's First 3-D Printer In Space Creates Its First Object

Newsy (Nov. 26, 2014) — The International Space Station is now using a proof-of-concept 3D printer to test additive printing in a weightless, isolated environment. Video provided by Newsy
Powered by NewsLook.com
Bolivian Recycling Initiative Turns Plastic Waste Into School Furniture

Bolivian Recycling Initiative Turns Plastic Waste Into School Furniture

Reuters - Innovations Video Online (Nov. 26, 2014) — Innovative recycling project in La Paz separates city waste and converts plastic garbage into school furniture made from 'plastiwood'. Tara Cleary reports. Video provided by Reuters
Powered by NewsLook.com
Who Will Failed Nuclear Talks Hurt Most?

Who Will Failed Nuclear Talks Hurt Most?

Reuters - Business Video Online (Nov. 25, 2014) — With no immediate prospect of sanctions relief for Iran, and no solid progress in negotiations with the West over the country's nuclear programme, Ciara Lee asks why talks have still not produced results and what a resolution would mean for both parties. Video provided by Reuters
Powered by NewsLook.com
Flying Enthusiast Converts Real-Life Aircraft Cockpit Into Simulator

Flying Enthusiast Converts Real-Life Aircraft Cockpit Into Simulator

Reuters - Innovations Video Online (Nov. 25, 2014) — A virtual flying enthusiast converts parts of a written-off Airbus aircraft into a working flight simulator in his northern Slovenian home. Jim Drury reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins