The XyM notation system is proposed as a linear notation for the electronic communication of structural formulas. Each XyM notation consists of a skeleton with such arguments as SUBSLIST, ATOMLIST, and BONDLIST. The arguments are designed to be capable of carrying out substitution derivation for placing large substituents, atom derivation for spiro fusion, and bond derivation for ring fusion. Additional arguments, SKBONDLIST and OMITLIST, are discussed for stereochemical and ring-opening information. The XyM notation system is implemented as a LaTeX2e application.