ISIS/Reactions (*.rxn)

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The ISIS/Reactions format is an MDL-developed format for storing chemical reaction information used by the ISIS family of products and others.

For single step single or multi-line reactions, ChemDraw uses the point of the reaction arrow as the dividing line to determine which molecules in a reaction are reactants and which are products.

NOTE: You cannot save a reaction with an intermediate step accurately in the RXN file format.

Molecules whose centers are behind or above the tip of the arrow are considered reactants, and all remaining molecules are products. The reaction arrow can be at any orientation; it does not have to be parallel to the x-axis. If a reaction contains multiple arrows, then the largest arrow is used as the reaction arrow.

Reaction mapping and reaction center information is stored in the rxn output file.