"Electric Fields Can Assist Prebiotic Reactivity on Hydrogen Cyanide Surfaces" ACS Central Science
A substance poisonous to humans - hydrogen cyanide - may have helped create the seeds of life on Earth. At cold temperatures, hydrogen cyanide forms crystals. And, according to computer models reported in ACS Central Science, some of the facets on these crystals are highly reactive, enabling chemical reactions that are otherwise not possible at low temperatures. The researchers say these reactions could have started a cascade that gave rise to several building blocks of life.
Adapted from ACS Central Science 2026, DOI: 10.1021/acscentsci.5c01497
"We may never know precisely how life began, but understanding how some of its ingredients take shape is within reach. Hydrogen cyanide is likely one source of this chemical complexity, and we show that it can react surprisingly quickly in cold places," says Martin Rahm, the corresponding author of the study.
Hydrogen cyanide is abundant in many environments beyond Earth, including on comets and the atmosphere of planets and moons (e.g., Saturn's moon Titan). Additionally, when combined with water, hydrogen cyanide can form polymers, amino acids and nucleobases (components of proteins and DNA strands, respectively). To further examine its chemical reactivity, Marco Capelletti, Hilda Sandström and Martin Rahm conducted computer simulations of frozen hydrogen cyanide.
The researchers simulated a stable hydrogen cyanide crystal as a 450-nanometer-long cylinder with a rounded base and a multifaceted top shaped like a cut gemstone. They say this shape matches prior observations of crystal "cobwebs" branching out from a central point, where the multifaceted ends come together.
Calculations revealed that the crystals have the potential to trigger chemical reactions that don't usually occur in extreme-cold environments. Using the chemical properties of the crystal surface, the researchers identified two pathways that could convert hydrogen cyanide into the more-reactive hydrogen isocyanide within minutes to days, depending on the temperature. They say that the presence of hydrogen isocyanide at the crystals' surface suggests that other, more complex prebiotic precursors could form there.
The team now hopes that other scientists will follow up on these predictions by performing experiments, in which hydrogen cyanide crystals are crushed in the presence of substances like water, to see if the exposed crystal surfaces can indeed encourage the production of complex molecules at extremely cold temperatures.
The authors acknowledge funding from the Swedish Research Council and the National Academic Infrastructure for Supercomputing in Sweden.
