Novichok-7 nerve agent, molecular model. Novichok (Russian: 'newcomer') refers to a new generation of chemical weapons that are far more lethal than any other nerve agents ever made. They were developed by the Soviet Union and Russia between 1971 and 1993. As cholinesterase inhibitors, they inhibit the acetylcholinesterase enzyme from breaking down the neurotransmitter acetylcholine. Exposure to a novichok agent poisoned several individuals (including Sergei and Yulia Skripal) in March and June 2018. Some novichok molecular structures were published in 2008 by Russian chemist Vil Mirzayanov. The molecular formula shown here (Novichok-7) is C10.H23.F.N3.O2.P. The atoms are colour-coded: carbon (dark grey), hydrogen (white), fluorine (green), nitrogen (blue), oxygen (red) and phosphorus (orange).