Researchers Rediscover the Structure of Water

February 26, 2010 by Kelen Tuttle
Researchers at SSRL recently determined the distances between the molecules in this jet of flowing water. (Image courtesy the research team)

( -- A team of researchers at the Stanford Synchrotron Radiation Lightsource has found the molecular structure of water to be more complex than recently thought, suggesting that molecular models that went out of fashion decades ago may be in fact more accurate than recent ones.

"The study of water has a very long history," said lead author Ling Fu, who is a postdoc at the Centre National de la Recherche Scientifique in France and who wrote her PhD thesis on these results. "Other researchers have done a very good job in their measurements; I hope that this work helps advance the field."

By recording how SSRL's X-ray beam scattered off a flowing jet of water, Fu and colleagues Arthur Bienenstock and Sean Brennan were able to determine the distances between the in the jet. As recent models predicted, they saw molecules 0.28 and 0.45 nanometers apart. These measurements confirm the current commonly accepted model, which describes liquid water as a group of water molecules held together in tetrahedral shapes, with the molecule at the center of the separated from four others at the shorter distance and each of these four molecules separated from one another at the longer distance.

Yet the researchers saw some molecules at a third distance as well: 0.34 nanometers. The existence of this third separation length, though not included in the current model, was first seen in 1938. Additional experiments in the 1960s and 1970s first confirmed, but later rejected, that this length exists, concluding that its detection was due to shortcomings in the analysis. As a result, models including this intermediate distance fell out of favor—until now.

That the SSRL researchers have now observed this intermediate separation length using modern-day technology suggests that "there's something more going on here" beyond the currently accepted model, Fu said.

These results suggest that liquid water's structure is not completely tetrahedral, but rather has some added complexity. But they do not fully solve the mystery of water's structure because the data taken at SSRL only reveal the distances between water molecules, not the angles of the bonds. "More research is needed to see the complete picture," said Brennan.

Fully understanding the structure of water is a surprisingly difficult task. In water's solid form, ice, the molecules are known to form a tight tetrahedral lattice. The current model holds that liquid water should be similar to ice but less structured since heat creates disorder and breaks bonds. In liquid , then, the tetrahedral structures would loosen their grip, breaking apart as the temperature rises, but still inclined to remain as tetrahedral as possible. This new research adds a kink in this theory, requiring some sort of secondary structure. The greater density of implies that the molecules are more closely packed than the simple tetrahedra seen in ice. These data help explain how that can happen.

The baton, Brennan said, is now in the hands of the theorists. "I think of this type of research as a relay race: The experimentalists run for a while until they can't explain something they've seen, and then the theorists run for a while until they can't go any farther without more data, and then it's back to the experimentalists," he said. "So, this time, we're saying that it's time for the theorists to run their leg."

Explore further: How Cagey Electrons Keep Hydrated

Related Stories

How Cagey Electrons Keep Hydrated

December 20, 2007

Water, despite its essential role in nature, remains a deeply mysterious substance. A long list of water's unusual properties tantalizes researchers even today, and scientists at the Stanford Synchrotron Radiation Laboratory ...

Scientists Observe Liquid Water Below Freezing

June 24, 2009

( -- Below 0 °C, water turns to ice. But beyond that, or below about -75 °C, the ice may turn back into liquid water. While scientists have previously predicted this phase transition with computer simulations, ...

Why Does Water Expand When it Cools? A New Explanation

July 17, 2009

( -- Most of us, when we take our first science classes, learn that when things cool down, they shrink. (When they heat up, we learn, they usually expand.) However, water seems to be the exception to the rule. ...

Researchers reveal the internal dance of water

August 12, 2009

( -- Water is familiar to everyone - it shapes our bodies and our planet. But despite this abundance, the molecular structure of water has remained a mystery, with the substance exhibiting many strange properties ...

Ice Gets Bent Out of Shape

September 9, 2009

For the first time, scientists have built completely flat, two-layer ice. While theoreticians have predicted that such ices are formed by squeezing water molecules between two surfaces, scientists at Pacific Northwest National ...

Recommended for you

New material science research may advance tech tools

August 31, 2015

Hard, complex materials with many components are used to fabricate some of today's most advanced technology tools. However, little is still known about how the properties of these materials change under specific temperatures, ...


Adjust slider to filter visible comments by rank

Display comments: newest first

5 / 5 (1) Feb 26, 2010
The problem of water structure is conceptually quite simple: you can imagine water droplet as tightly closed sack with many balls inside. The sack with spherical particles will be elastic and it will return into its spherical shape after deform fast - but when these particles will be formed by shaped rods, the tighten sack becomes plastic. I.e. it will retain it's shape after deform, because irregular particles cannot exchange their positions inside of sack so easily. The fluid composed of irregular particles simply cannot flow freely, it behaves like thin jelly or plasticine.

The whole trick at the case of water is, these phenomena applies only to quite tiny distance, to which hydrogen bonds are relevant - so that at the macroscopic scale the water behavior doesn't differ very much from common fluid behavior.
5 / 5 (1) Feb 26, 2010
Due the strong internal pressure water molecules are oligomerising into form of rigid water clusters of icosahedral symmetry. The water cluster evidence is based on X-ray spectroscopy, by which exists only two hydrogen bridges are available per molecule, so that the formation of chained flat structures similar to sponge or foam is preferred.


I believe, this behavior would be rather easy to simulate by ab-initio calculations of interactions of water molecules inside of water clusters - only the relatively large number of particle involved makes it difficult to describe by formal math. Mainstream physics isn't really good in description of multiparticle emergent phenomena, for example the formal description of HT superconductivity is a problem of similar category.
2.6 / 5 (5) Feb 26, 2010
And both of your comments have zero to do with the article.
3 / 5 (2) Feb 26, 2010
And both of your comments have zero to do with the article.
The more the above sentence of yours - it could be used under whatever comment. It's easy to say such sentence - but how can you prove your stance?
3 / 5 (6) Feb 26, 2010
And both of your comments have zero to do with the article.

Feb 26, 2010
This comment has been removed by a moderator.
5 / 5 (1) Feb 26, 2010
reminds me of the slinky coil effect
Water clusters are quite rigid and they're exhibiting inertia because of larger number of water molecules involved. For example during passing of radio-waves they're behaving like larger pebbles in the sack being shaken, thus eroding elements of water by their inertia.

In this way I imagine the splitting of hydrogen bounds in water during passing of quite low frequency radiowaves.


Without presence of clusters the water would behave like sand in box, during shaking of which no observable abrasion occurs, because of low inertia of tiny particles.

BTW In this way we could explain the cold fusion of deuterions in palladium lattice, where these particles are forming more compact clusters, too. Maybe the energizing of palladium lattice saturated by deuterium would be the key to cold fusion. For example, prof. Arata used laser pulses for these purposes.
3.5 / 5 (2) Feb 26, 2010
The huge contraction of watter during melting demonstrates the brutal pressure exerted by hydrogen bonds to asymmetric molecules of watter. The water collapses by one tenth of volume during this, which corresponds the pressurizing of water by more then 30.000 atm. This explains huge amount of heat released during melting of ice, too.


The huge intrinsic pressure between water molecules manifests for example by slipperiness of ice, which is covered by thin layer of liquid watter even bellow -53 °C.


Inside of this thin layer of water ballistic transport of water molecules occurs - the water is partially in superfluous state here. This could explain crackling and crunching of fresh cold snow under your feet. In hellium with perfectly spherical atoms such supersolidity could be observed just bellow few Kelvin temperature!
not rated yet Feb 27, 2010
And both of your comments have zero to do with the article.
The more the above sentence of yours - it could be used under whatever comment. It's easy to say such sentence - but how can you prove your stance?

Go read the article, then read your comments and you tell me.
not rated yet Feb 27, 2010
Missing diagrams? This sounds very interesting, but I find it hard to visualize. I'd love to see a graphic of what actually was identified.
not rated yet Feb 27, 2010
Maybe the third water molecule distance comes from interaction with some of the water present in the air?
not rated yet Feb 27, 2010
Research suggest that liquid water contains significant numbers of broken hydrogen bonds and is better described as rings of strongly H-bonded chains rather than the tetrahedral structure observed in ice. For background reading you can visit


Horizontal water jet was used, because it eliminates scattering from a container and precludes radiation-induced bubble formation from the intensive X-ray SPEAR3 source.
5 / 5 (1) Feb 27, 2010
I'd love to see a graphic of what actually was identified
In ice, each water molecule is surrounded by four other molecules in a tetrahedral arrangement (left). This new result on liquid water shows that the molecules are connected only with two others. This implies that most molecules are arranged in strongly hydrogen-bonded rings (middle) or chains (right) embedded in a disordered cluster network connected mainly by weak hydrogen bonds. The oxygen atoms are red and the hydrogen atoms are gray in the water (H2O) molecules.
3 / 5 (2) Feb 27, 2010
There exists an analogy of this behavior, which can be visualized by passing of polarized through transparent polyacrylate beads submerged in water.


It's apparent, under stress emergent linear pattern emerge in packing structure of beads. In water these patterns are of sparse icosahedral structure.

This phase transition has a deeper meaning in aether theory and in string heterotic theories, which are based on most effective hypersphere packing density. The high internal stress of water molecules results into compactification of octahedral structure into icosahedral one in process of so called heterosis. In LQG theory this process is described by dynamic causual triangulation. Compare the Aristotelian theory of four elements, where watter is assigned just to icosahedron Platonic solid.
not rated yet Feb 28, 2010
All of the above simply ends up showing that Stan Myers (RIP) and other HHO proponents (RIP for some) were and are on the exact right track when it comes to breaching the atomic bonds of water to create HHO or to separate into hydrogen and oxygen -- in an extremely efficient manner.

Snooze---you loose. Alternate takes and research have always been ahead of the mainstream, and always will be. The leading edge is never in the textbooks, and never will be.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.