Novichok

A class of organophosphate nerve agents developed under the Soviet Union's Foliant programme, structurally distinct from G-series (sarin, tabun, soman) and V-series (VX) agents. Not previously listed in CWC Schedule 1 at the time of the Salisbury attack; subsequently added to Schedule 1 by the Conference of States Parties. Characterised by high acute toxicity and environmental persistence in formulated gel form.