A Deadly Chemical Called Hydrogen Cyanide Frozen in Ice May Have Helped Start Life on Earth
A very dangerous chemical that is poisonous to humans may have played a surprising role in how life first began on Earth. This chemical is called hydrogen cyanide. Scientists now believe it may have helped start the chemical reactions that eventually led to life.
Hydrogen cyanide can freeze at very low temperatures and form solid crystals. New computer studies published in ACS Central Science show that when this chemical is frozen, the surface of its ice crystals becomes highly reactive. These surfaces can make chemical reactions happen even in extreme cold, where reactions usually stop. Because of this, frozen hydrogen cyanide could have helped create important molecules needed for life.
The researchers say these reactions may have started a chain process that produced some of life’s basic building blocks. This also suggests that frozen planets and moons may be more chemically active than scientists once believed.
Martin Rahm, the lead author of the study, explains that scientists may never know exactly how life began. However, they can still study how life’s basic ingredients formed. He says hydrogen cyanide is likely one source of this early chemical complexity and that it can react much faster in cold environments than expected.
Hydrogen cyanide is not rare in space. Scientists have already found it on comets and in the atmospheres of planets and moons, including Saturn’s moon Titan. When hydrogen cyanide mixes with water, it can form polymers, amino acids, and nucleobases. These are important parts of proteins and DNA.
To understand how this chemical behaves when frozen, researchers Marco Capelletti, Hilda Sandström, and Martin Rahm used computer models. They studied a frozen hydrogen cyanide crystal shaped like a long cylinder about 450 nanometers long. The crystal had a rounded bottom and a top with several flat faces, similar to a cut gemstone. This shape matches earlier observations of crystal patterns called “cobwebs,” which spread out from a central point.
The simulations showed that these frozen crystals can trigger chemical reactions even in extreme cold. The researchers found two ways that hydrogen cyanide could change into hydrogen isocyanide, which is even more reactive. Depending on the temperature, this change could take just minutes or several days. Once hydrogen isocyanide forms on the crystal surface, it becomes easier for more complex molecules to develop.
The research team hopes scientists will now test these ideas in laboratories. One suggested experiment involves crushing frozen hydrogen cyanide crystals near water to expose fresh surfaces. Researchers could then watch to see if complex molecules form in very cold conditions, helping confirm these findings.
