Topic: Chemistry

Brown University chemists found that heavy elements like bismuth form bonds differently than expected. They used photoelectron spectroscopy to show that relativity affects how atoms bond, changing the structure of triple bonds.

Scientists at Brown University have made a surprising discovery about how atoms bond in heavy elements. In a study published in Science, they found that when atomic nuclei are very heavy, the principles described in Einstein's theory of relativity change the way atoms form bonds.

The researchers used a technique called photoelectron spectroscopy to analyze molecules made from bismuth and carbon. Bismuth is a heavy element that should be affected by relativistic effects. They cooled the molecules to near absolute zero and then used a laser to knock individual electrons out of their positions in the molecule. The distance each electron flew told them how strongly it was bound.

The photoelectron spectrum showed that the carbon-bismuth bonds did not fit the traditional triple-bond picture of one sigma bond and two pi bonds. Instead, the structure looked more like one pi bond and two hybrid sigma-pi bonds. This means that the boundary between a sigma bond and a pi bond is now 'smeared'.

The study's corresponding author, Lai-Sheng Wang, said that this discovery may lead to a rewriting of chemistry textbooks. He noted that the idea that relativity is important in heavy elements has been around since the 1970s, but this is the first direct spectroscopic evidence.

Why It Matters

This discovery can help us better understand how atoms bond in heavy elements, which is important for developing new materials and technologies. It also shows how our current understanding of chemistry may need to be revised.

Key Facts

• Brown University chemists found that relativity affects the way atoms bond in heavy elements like bismuth.
• The study used photoelectron spectroscopy to analyze molecules made from bismuth and carbon.
• The traditional triple-bond picture of one sigma bond and two pi bonds does not apply to heavy elements.
• The structure of carbon-bismuth bonds looks more like one pi bond and two hybrid sigma-pi bonds.
• This discovery may lead to a rewriting of chemistry textbooks.

Key Terms

Relativity

A theory developed by Albert Einstein that describes how space and time are connected.

Photoelectron spectroscopy

A technique used to analyze the energy levels of electrons in a molecule.

Sigma bond

A strong, 'head-on' bond between two atomic nuclei.

Pi bond

A weaker, 'side-by-side' bond that wraps around a sigma bond.

Implications

This discovery can help us better understand how atoms bond in heavy elements, which is important for developing new materials and technologies. It also shows how our current understanding of chemistry may need to be revised.