A NOMENCLATURE AND STRUCTURAL REPRESENTATION SYSTEM FOR LADDER AND SPIRO POLYMERS

A ''ring-by-ring'' nomenclature and structural representation system f or ladder and spiro polymers is presented. This novel system differs m arkedly from the International Union of Pure and Applied Chemistry (IU PAC) and Chemical Abstracts Service (GAS) systems, which require ring fracture, naming of complete ring assemblies, and occasional use of no menclature to determine final orientation of structural repeating unit s (SRUs). The advantages of the system presented are as follows: SRU i dentification and orientation are completely independent of nomenclatu re; no rings are fractured; and each individual ring is named separate ly (except in one rare and precisely defined situation) and thus names of complete ring assemblies are not required.