Scientists isolate two different forms of water

Two different water forms (blue or red arrows) react with the diazenylium atoms at different speeds

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Scientists have isolated two different forms of water molecules for the first time.

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Water molecules are known to exist as two different "isomers", or types, based on their slightly different properties at the atomic level.

By separating the two isomers, researchers were able to show that they behave differently in the way they undergo chemical reactions.

The work appears in Natural Communications.

In basic terms, the water molecule consists of a single oxygen atom attached to a pair of hydrogen atoms.

However, they can be subdivided by the nature of the nucleus at the heart of the hydrogen atom - their "spin".

While they do not rotate in the sense we will understand, the nature of this hydrogen nucleus affects the rotation of the water molecule itself.

If the nuclear spins from two hydrogen atoms in the same oriented water, it is called ortho-water. If they are arranged in different directions, it is known as para-water.

Since the isomers are very similar, it is very difficult to separate them. But the co-author, Prof Stefan Willitsch and his colleagues managed to do so using an electric field.

They can then investigate how various forms of water react with other chemicals.

They used a diazenylium ultracold ion (a nitrogen form) for this test. The researchers found that the water-water reacts about 25% faster with diazenylium than ortho-water.

Since the rotation of the H2O molecule is affected by nuclear rotation, different tensile forces act between the counterparts in this chemical reaction. The researchers support this interpretation using computer modeling.

Professor Willitsch said the research could help improve control over other types of chemical reactions: "Better able to control the state of molecules involved in chemical reactions, the better the underlying mechanism and the dynamics of the reaction can be investigated and understood."