rational formula
 半理論公式; 半有理式


 For·mu·la n.; pl. E. Formulas L. Formulæ
 1. A prescribed or set form; an established rule; a fixed or conventional method in which anything is to be done, arranged, or said.
 2. Eccl. A written confession of faith; a formal statement of foctrines.
 3. Math. A rule or principle expressed in algebraic language; as, the binominal formula.
 4. Med. A prescription or recipe for the preparation of a medicinal compound.
 5. Chem. A symbolic expression (by means of letters, figures, etc.) of the constituents or constitution of a compound.
 Note: ☞ Chemical formulæ consist of the abbreviations of the names of the elements, with a small figure at the lower right hand, to denote the number of atoms of each element contained.
 Empirical formula Chem., an expression which gives the simple proportion of the constituents; as, the empirical formula of acetic acid is C2H4O2.
 Graphic formula, Rational formula 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.
 Molecular formula Chem., a formula indicating the supposed molecular constitution of a compound.

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