c. CW binary precursors and key precursors, as follows, and chemical mixtures containing one or more of these precursors: 1. Alkyl (Methyl, Ethyl, n-Propyl or Isopropyl) Phosphonyl Difluorides, such as: DF: Methyl Phosphonyldifluoride (CAS 676-99-3); 2. O-Alkyl (H equal to or less than C , including cycloalkyl) O-2-dialkyl (Methyl, Ethyl, n-Propyl or Isopropyl)-aminoethyl alkyl (Methyl, Ethyl, n-Propyl or Isopropyl) phosphonites and corresponding alkylated and protonated salts, such as: 10 QL: O-Ethyl O-2-di-isopropylaminoethyl methylphosphonite (CAS 57856-11-8); 3. Chlorosarin: O-Isopropyl methylphosphonochloridate (CAS 1445-76-7); 4. Chlorosoman: O-Pinacolyl methylphosphonochloridate (CAS 7040-57-5);