American Scientist

Sergei Skripal and his daughter Yulia were poisoned on March 4. On March 13, the British government revealed that it is believed that a type of Novichok agent was the chemical culprit behind the attempted murder. Novichok agents are organophosphate nerve agents. Novichok loosely translates to newcomer in Russian. Chemically, they are similar to the V series of organophosphate agents, which includes VX, and the G series, which includes sarin.

What we know about Novichok agents is largely as a result of information divulged by a former Russian chemical weapons scientist, Vil Mirzayanov. In 1992, Mirzayanov, along with his colleague Lev Fedorov, published an article in a Russian newspaper detailing aspects of Russia’s development of nerve agents, despite the imminent signing of the Chemical Weapons Treaty. Mirzayanov and Fedorov claimed that the Novichok agents were developed from the 1970s up to the early 1990s.

The structures of the Novichok agents remain unclear. Though they have been speculated on, and some suggested structures have appeared in books and journals, these structures differ from what Mirzayanov claims represent typical Novichok agents. He published a series of structures in his autobiography in 2008, shown in the graphic above. He also suggested that there were many more compounds produced and that the structures of the less potent compounds were openly reported as organophosphate insecticides to cover for the chemical weapons program. Mirzayanov stated that the Novichok agents are binary compounds; that is, they can be formed by the combination of two different compounds that are safer to handle, making it possible to make them on demand. The exact precursor compounds used are not known. It is reported that some of the Novichok agents can be up to ten times more lethal than VX, which can kill if a person’s skin is exposed to just ten milligrams. —Andy Brunning