TEHRAN (Press Shia) – Scientists have captured the first ever footage of atoms bonding at a scale around half a million times smaller than the width of a human hair.
Using advanced microscopy methods, the team of UK and German researchers captured the breaking of a chemical bond between two rhenium atoms.
The video shows the two atoms to the left of the footage, between 0.1 and 0.3 nanometres, appearing as black blobs as they bond and break, the Daily Mail reported.
Atoms are “the building blocks of the world” and the matter around us is made up of layers and layers of atoms – unless they’re a single-layer material like graphene.
Ultimately, everything is controlled by the way atoms interact – they account for explosions, chemical processes inside the human body and how the sun generates energy.
Now, this breaking and formation of the two bonds has been recorded on film at the atomic scale.
“It was surprisingly clear how the two atoms move in pairs, clearly indicating a bond between them,” said Dr Kecheng Cao, research assistant at the University of Ulm in Germany, who performed the imaging experiments.
“Importantly, as Re2 moves down the nanotube, the bond length changes, indicating that the bond becomes stronger or weaker depending on the environment around the atoms.”
Filming chemical bonds breaking or forming in real time is a great challenge due to their nanoscopic size.
The team used a method called transmission electron microscopy (TEM) – where a high-energy beam of electrons is shone through a very thin sample.
In this case, the researchers used carbon nanotubes as their sample – atomically thin hollow cylinders of carbon with diameters at the molecular scale (1-2nm), as ‘miniature test tubes’ for the atoms.
“Nanotubes help us to catch atoms or molecules, and to position them exactly where we want,” said Professor Andrei Kholbystov, professor of nanomaterials at the University of Nottingham.
“In this case we trapped a pair of rhenium (Re) atoms bonded together to form Re2.
“Because rhenium has a high atomic number it is easier to see in TEM than lighter elements, allowing us to identify each metal atom as a dark dot.”
Once bonded, the Re2 atoms are shown to vibrate, distorting their circular shape to become ovals and stretching the bond between them.
The atoms eventually snapped and vibrations ceased, but a little later the atoms joined together again, reforming an Re2 molecule.
“What makes it challenging is that transition metals, such as Re, can form bonds of different order, from single to quintuple bonds,” said Dr Stephen Skowron, Postdoctoral Research Assistant at University of Nottingham.
“In this TEM experiment we observed that the two rhenium atoms are bonded mainly through a quadruple bond, providing new fundamental insights into transition metal chemistry.
“Bonds between metal atoms are very important in chemistry, particularly for understanding magnetic, electronic, or catalytic properties of materials.”
The team believe electron microscopy may become a general method for studying chemical reactions, similar to spectroscopic methods widely used in chemistry labs, which use light rays.
The researchers, from the University of Nottingham and the University of Ulm, detailed their achievement in the journal Science Advances.