There's an absolutely terrifying book by Ken Alibeck ("Biohazard") about the Soviet secret chemical and biological warfare programme. (https://en.wikipedia.org/wiki/Ken_Alibek)
Also look at State Secrets: An Insider's Chronicle of the Russian Chemical Weapons Program by Vil S Mirzayanov, Novichok is covered there as well. ( https://www.amazon.com/gp/product/1432725661/ref=oh_aui_sear... nonref)