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SciFinder Scholar | CAS Online | Standard Abbreviations | Index Guide | Guide to CASREACT | Structure Searching with STN Express

Structure searching in CAS Online using STN Express: An introductory workshop

Types of structure searches: Closed substructure search (CSS)

• CSS search retrieves substances which match the query exactly
  • All positions in query are blocked for further substitution
  • All query rings are isolated
  • Variable nodes are allowed in the query
  • Retrieves all substances having the same connection table
    • Unsubstituted substance
    • Stereoisomers
    • Isotopically labelled substances
    • Radicals
    • Ions
    • Homopolymers
  • Retrieves multi-component substances that have the query as one of the components
• Any position may be opened to substitution by specifying the connectivities for the node