Atoms are the building blocks of the world. Everything around us is based on that one chemical process in which two atoms bind and form matter. Yet researchers know very little about how and why atoms connect to each other. A research team wanted to change that. And with success. A new study succeeded in making a video clip for the first time showing how a chemical connection is established.
Whether it is a molecule (that is made up of atoms that are connected to each other in a fixed arrangement of chemical compounds), or a fully living organism: in the end everything is determined by the way atoms bind and the way bonds break. However, this is very difficult to fathom. The length of chemical compounds is namely between 0.1 and 0.3 nanometers, or; about half a million times smaller than the width of a human hair. This makes it almost impossible to observe the bond between a few atoms directly.
However, a new research team did not get upset. They decided to make the impossible possible and decided to create a groundbreaking video showing how atoms connect to each other. A true scoop: this has never been successful before. To record the process, the researchers locked a few rhenium atoms – a type of chemical element of heavy metals – into narrow carbon nanotubes. These are very small thin, hollow cylinders of carbon that serve as test tubes for the atoms. “Nanotubes help us to capture atoms and molecules and place them exactly where we want,” explains researcher Andrei Khlobystov. “In this case, we opted for rhenium atoms. That is because this atom is easier to see than lighter elements so that we could recognize each metal atom as a dark dot. “
The special video can be seen above. The 18-second video shows how two atoms hopping around, then slowly getting closer together and eventually merging. That only takes a while. The dot jumps around before the connection is broken again. Moments later, the atoms converge again and then form the Re2 molecule. “It was surprising how the two atoms move, which clearly indicates a bond between the two,” says researcher Kecheng Cao. “It is important that when Re2 moves down the nanotube, the binding length changes. This indicates that the bond becomes stronger or weaker, depending on the environment around the atoms. “
Connections between metal atoms are very important in chemistry, in particular for understanding the magnetic, electrical or catalytic properties of materials. However, what makes it such a challenge is that transition metals – such as Re – can form connections with different sequences; from single to five-fold connections. In the current experiment, the researchers found that the two rhenium atoms are mainly connected via a quadruple compound, which provides new fundamental insights into the chemistry of transition metals.
The short film is an exceptional achievement. “As far as we know, this is the first time that the confluence, breaking and forming of the connection has been recorded on an atomic scale on video,” says Khlobystov. “We are pushing boundaries and are increasingly moving into the dynamics of individual molecules in real time to understand.”