Graphic formula , Rational formula Meaning, Definition & Usage

Definitions
  1. (Chem.), an expression of the constitution, and in a limited sense of the structure, of a compound, by the grouping of its atoms or radicals; as, a rational formula of acetic acid is CH3.(C:O).OH; called also structural formula, constitutional formula, etc. See also the formula of Benzene nucleus, under Benzene.

Webster 1913