Albert Einstein鈥檚 theory of special relativity can reshape chemical bonds within molecules, and researchers have just seen it happen for the first time.

The theory of special relativity describes how moving at speeds close to the speed of light would affect travellers鈥� experience of space and time. Because of this, it is usually associated with particle accelerators and spacefaring objects, but within some heavy atoms, electrons experience relativistic speeds too.

at Brown University in Rhode Island and his colleagues have now managed to take an unprecedented look at how this breaks the standard notion of chemical bonds within a charged molecule made from bismuth and carbon.

Within the molecule, a bismuth atom and a carbon atom were connected by three bonds, one of which the researchers expected to be of 鈥渟igma鈥� type and two of 鈥減i鈥� type. The difference between these two types stems from electrons鈥� quantum character 鈥� each electron is 鈥渟meared鈥� across some region of space, instead of being a tight ball, and whether these regions overlap head on or side by side determines the type of chemical bond they create between the atoms.

In their experiment, Wang and his colleagues mapped the distribution of electrons throughout the molecule, effectively getting a look at its bonds. But instead of seeing electrons distributed in shapes associated with sigma and pi bonds, the team noticed that two of the bonds resembled two different mixes of sigma and pi shapes. 鈥淭heir characters are different from our normal understanding,鈥� says Wang. 鈥淵ou can鈥檛 really call it the sigma and pi.鈥�

His team turned to at Washington State University, whose calculations ultimately showed that this mixing was a consequence of electrons near the bismuth nucleus feeling such a strong electromagnetic interaction that they moved at relativistic speeds. He says this effect hadn鈥檛 previously been captured in an experiment.

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鈥淭he hardest thing about [studying] heavy elements is a lack of really good experimental data,鈥� says Peterson. 鈥淭o have such a beautiful experiment to be able to essentially compare very high-level theory to data is really a luxury.鈥�

Wang says one important part of the new experiment is that he and his colleagues could make the molecule very cold before looking at its electrons. This dampened any jitters and excitations that would have made the final images imprecise.

鈥淎s you go down to the bottom of the periodic table, the usual quantum mechanics is no longer sufficient, you need to take into account the effects of relativity,鈥� says at the University of Toulouse in France. He says that all elements in the same row of the periodic table as bismuth are affected by relativistic effects 鈥� for instance, gold would be the same colour as silver and mercury would not be liquid without them.

at the University of Helsinki in Finland says that for bismuth, the relativistic effect on its bonding with carbon could influence how organic bismuth compounds are used in chemical reactions. In fact, by researchers at the Max Planck Institute for Coal Research in Germany has already shown that relativistic effects help make this heavy metal a good catalyst, or accelerator, of chemical processes.

Wang says that the team now wants to repeat their experiment but swap bismuth for elements close to it in the periodic table to see when exactly special relativity makes the traditional chemical bond structure collapse.

Chemists have discovered a new molecular shape, and it is twice as odd as the twisty M枚bius strip.

The M枚bius strip is a looped band with a twist, such that something tiny, such as an ant, would have to go around the loop twice to return to where it started on the same side of the strip.

at the University of Manchester in the UK and his colleagues now discovered a molecule with an even stranger 鈥渉alf-M枚bius鈥� shape. Their experiment may be the first step towards a new way to engineer useful molecules by tuning their 3D shapes, or topology.

鈥淭his molecule is very new and very unexpected. The appeal is not just that we made a molecule with an unusual topology, but we also showed that this topology is possible, and no one really thought about it,鈥� he says.

To make the molecule, the researchers used 13 carbon atoms and two chlorine atoms assembled into a ring-like shape on a thin surface of gold at an extremely cold temperature. They used two specialised microscopes 鈥� an atomic force microscope and a scanning tunnelling microscope 鈥� to control the atoms and map the properties of their electrons. In this type of molecule, the electrons aren鈥檛 tightly bound to their atoms; instead, the electrons spread across specific regions around the atoms like tiny waves of matter.

It was the interactions between these electrons that produced the never-before-seen twistiness in the molecule. If a tiny quantum creature travelled along the atoms, it would take it four circuits of the ring to return to its starting point.

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By prodding the molecule with a small electromagnetic pulse, the team was able to switch the molecule鈥檚 twist from left-handed to right-handed or to untwist it. The researchers could engineer its topology on demand, creating another way for chemists to manipulate molecules.

To understand the new molecule and why it could even exist, the team used simulations on both a conventional computer and an IBM quantum computer. Interactions between electrons were crucial for the molecule鈥檚 novel twists, and they are difficult to exactly simulate with conventional computers. But quantum computers are already built from interacting quantum objects, so they can perform simulations at a higher level of confidence, says Ron膷evi膰.

This is an example of how quantum computers can already be useful for real-world chemistry problems, says team member at IBM.

鈥淭his experiment is a remarkable achievement across a number of dimensions: organic chemistry, surface science, nanoscience and quantum chemistry,鈥� says at the University of Copenhagen in Denmark.

鈥淭his is a beautiful and inspiring study that brings abstract topological concepts vividly into the realm of molecular chemistry,鈥� says at the Japanese scientific institute RIKEN. He says the study is a technical tour de force.

at Yonsei University in South Korea, a pioneer of past work on M枚bius-like molecules, says being able to switch the molecule from one shape to another is particularly interesting, as it could lead to applications in sensors. For instance, molecules could switch in a pre-programmed way when exposed to magnetic fields.

According to the RNA world hypothesis, life began when RNA molecules evolved the ability to make more copies of themselves. Now we have discovered an RNA molecule that is almost capable of this 鈥� it can carry out the key steps involved, just not all at once.

鈥淚t鈥檚 been a long quest to get to the point where you can convince yourself that RNA has the capacity to make itself under the right conditions. I think this shows that it is possible,鈥� says at the MRC Laboratory of Molecular Biology in Cambridge, UK.

In living cells, proteins carry out key tasks such as catalysing chemical reactions, and the recipes for making them are stored in double-stranded DNA molecules. RNA is a chemical cousin of DNA that usually exists in the form of single strands.

It isn鈥檛 as good for storing information as DNA because it is less stable, but it can do something DNA can鈥檛: fold up to form protein-like enzymes that can catalyse chemical reactions. Because RNA can both store information and act as a catalyst, it was suggested as early as the 1960s that life might have begun with RNA molecules capable of catalysing their own formation.

But finding such molecules has proved really difficult. Researchers had long assumed that self-replicating RNAs must be relatively large and complex, but it turns out to be very hard to unfold large RNAs to replicate them.

What鈥檚 more, while it has been shown that relatively short RNA molecules can form spontaneously in the right conditions, large molecules are very unlikely to have done so.

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鈥淭his led us to think, well, maybe we鈥檙e wrong. Maybe something simple, something small, could carry out this process,鈥� says Holliger. 鈥淎nd so we went looking, and we found one.鈥�

RNAs are made of building blocks called nucleotides. The team started by generating a trillion random sequences that were 20, 30 or 40 nucleotides long. From these, they picked out three that could carry out reactions such as joining nucleotides together. The three were joined together and put through several rounds of evolution 鈥� randomly changing, or mutating, parts of the sequence and selecting the better-performing variants.

The resulting molecule, called QT45, is just 45 nucleotides long. In alkaline water that is just above freezing, it can use single-stranded RNA as a template for making complementary strands by joining together short strands of two or three nucleotides,聽including making a sequence complementary to its own. 鈥淚t鈥檚 currently quite slow and low-yielding, but that鈥檚 not a surprise,鈥� says Holliger.

QT45 can also make more copies of itself from those complementary strands. 鈥淭his is, for the first time, a piece of RNA that can make itself and its encoding strand, and those are the two constituent reactions of self-replication,鈥� says Holliger. But so far, the team hasn鈥檛 managed to get both reactions to happen in the same container. The plan is now to both evolve the molecule further and experiment with conditions such as freeze-thaw cycles to see if both reactions could happen at once.

鈥淭he most exciting thing is, once the system begins to self-replicate, it should become self-optimising,鈥� Holliger says. That鈥檚 because the error-ridden process will produce a lot of variations, a few of which may work better, producing more of themselves, and so on.

鈥淭he new results from the Holliger lab are exceptional and a significant advance, pushing things even closer to a fully self-replicating RNA,鈥� says at the University of Greifswald in Germany.

鈥淧erhaps the most significant aspect of this finding is to discover a moderately sized RNA oligomer sequence with these self-synthesising capabilities,鈥� says at the University of Wisconsin-Madison.

The number of 45-nucleotide-long RNA sequences alone is 鈥渦nimaginably large鈥�, Adam points out, so the team did well to find QT45 from a starting point of just a trillion random sequences.

On the early Earth, molecules similar to QT45 might have been able to self-replicate in an environment a bit like modern-day Iceland, Holliger says, with ice present, but also hydrothermal activity to drive freeze-thaw cycles and create pH gradients. Some sort of compartmentalisation would be needed to isolate the key components, he thinks, but there are many ways this can happen, from pockets of meltwater in ice to cell-like vesicles forming spontaneously from fatty acids.