A new study suggests that hydrogen cyanide, a highly poisonous chemical, could have played a key role in the origins of life by forming reactive ice crystals in extreme cold. Computer simulations show these crystals promote unusual chemical reactions that produce building blocks for life. The findings highlight the chemical potential of frozen environments, including those beyond Earth.
Hydrogen cyanide, known for its toxicity to humans, freezes into crystals at low temperatures, creating surfaces that are unusually reactive. Researchers used computer modeling to examine these crystals, revealing that they can drive chemical processes typically impossible in frigid conditions. The study, published in ACS Central Science, indicates that such reactions might have initiated the formation of life's fundamental components.
The team, led by Martin Rahm, modeled a hydrogen cyanide crystal resembling a 450-nanometer-long cylinder with a rounded base and multifaceted top, akin to earlier observations of "cobweb" formations. Their simulations identified two pathways converting hydrogen cyanide to the more reactive hydrogen isocyanide, occurring in minutes to days depending on temperature. This compound on crystal surfaces could facilitate the creation of complex prebiotic molecules.
"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," Rahm stated.
Hydrogen cyanide is common in space, detected on comets and in atmospheres like that of Saturn's moon Titan. Interacting with water, it forms polymers, amino acids, and nucleobases—essentials for proteins and DNA. The researchers, Marco Cappelletti, Hilda Sandström, and Rahm, propose lab tests, such as crushing crystals with water to expose surfaces and observe molecule formation in cold settings.
Funded by the Swedish Research Council and Sweden's National Academic Infrastructure for Supercomputing, the work underscores that icy worlds may be more chemically active than previously assumed, with implications for prebiotic chemistry on early Earth and elsewhere.