Combating Decay: Novel Building Block for Chemistry Developed

An international research team with the participation of Karlsruhe Institute of Technology (KIT) has achieved a previously unattained goal in chemistry: It produced the first triply positively-charged molecule based on atoms of the semimetal antimony. Such highly-charged molecules normally decay quickly because charges repel each other. The open structure is also special: metal atoms are rarely arranged in this way, as ring-shaped structures are typically more stable. To date, researchers had only been able to identify related molecules with a single positive charge.

An Auxiliary Molecule Holds the System Together

The three antimony atoms are “held together” from the outside by bis(phosphane) ligands. They distribute the high charge, thereby preventing the antimony atoms from repelling each other. “As a result, despite its internal strain, the molecule remains stable enough to be isolated in crystalline form and studied,” explains Professor Stefanie Dehnen from the Institute of Nanotechnology (INT) at KIT. Overall, however, the novel chemical building block remains highly reactive. The complex bonding relationships were elucidated through theoretical studies by Professor Florian Weigend from the Institute for Quantum Materials and Technologies at KIT.

The work opens up new fields of research for molecular and materials sciences. Antimony compounds, for example, are of interest for the development of new thermoelectric materials that can be used to generate electricity from temperature differences.

“Our results are likely to stimulate broader interdisciplinary research into systems containing atoms of heavy elements such as antimony. We are excited to see what comes next!” said lead author Professor Moumita Majumdar from the Indian Institute of Science Education and Research, Pune, who was recently appointed an “International Associated Researcher” at INT.

iha, April 29, 2026