tl;dr: Brown University chemists used photoelectron spectroscopy on carbon-bismuth molecules to show that triple bonds in heavy elements don't follow the textbook one-sigma-plus-two-pi structure. Due to relativistic effects (spin-orbit coupling) in heavy nuclei, the bonds instead appear as one pi bond and two hybrid sigma-pi bonds. The finding provides direct experimental evidence for a long-theorized relativistic bonding regime and could prompt textbook revisions as heavy elements like bismuth gain importance in solar cells and quantum computing research.