molecular formula

molecular formula
molecular formula mo*lec"u*lar form"u*la, n. (Chem.) An expression representing the composition of elements in a chemical substance, commonly consisting of a series of letters and numbers comprising the atomic symbols of each element present in a compound followed by the number of atoms of that element present in one molecule of the substance. Thus the molecular formula for common alcohol (ethyl alcohol) is {C2H6O}, meaning that each molecule contains two carbon atoms, six hydrogen atoms, and one oxygen atom. The molecular formula may be written to provide some indication of the actual structure of the molecule, in which case structural units may be written separately. Thus, ethyl alcohol can also be written as {CH3.CH2.OH} or {CH3-CH2-OH}, in which the period or dash between functional groups indicates a single bond between the principle atoms of each group. This formula shows that in ethyl alcohol, the carbon of a methyl group ({CH3-}) is attached to the carbon of a methylene group ({-CH2-}), which is attached to the oxygen of a hydroxyl group ({-OH}). A {structural formula} is a graphical depiction of the relative positions of atoms in a molecule, and may be very complicated. [PJC]

The Collaborative International Dictionary of English. 2000.

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  • Molecular formula — Formula For mu*la, n.; pl. E. {Formulas}, L. {Formul[ae]}. [L., dim. of forma form, model. See{Form}, n.] 1. A prescribed or set form; an established rule; a fixed or conventional method in which anything is to be done, arranged, or said. [1913… …   The Collaborative International Dictionary of English

  • molecular formula — n a chemical formula for a compound existing as discrete molecules that gives the total number of atoms of each element in a molecule <the molecular formula for water is H2O> see STRUCTURAL FORMULA compare EMPIRICAL FORMULA * * * a chemical …   Medical dictionary

  • molecular formula — n. a formula which gives the kinds of atoms or radicals and the number of each kind in the molecule of a compound (Ex.: C6H6 for benzene) …   English World dictionary

  • molecular formula — noun A notation indicating the number of atoms of each element present in a compound. The molecular formula for ethane is CH, while the empirical formula is CH …   Wiktionary

  • molecular formula — molekulinė formulė statusas T sritis chemija apibrėžtis Formulė, rodanti junginio molekulę sudarančių kiekvieno elemento atomų skaičių. atitikmenys: angl. molecular formula rus. молекулярная формула …   Chemijos terminų aiškinamasis žodynas

  • molecular formula — noun a chemical formula based on analysis and molecular weight • Hypernyms: ↑formula, ↑chemical formula • Hyponyms: ↑structural formula …   Useful english dictionary

  • molecular formula — Chem. a chemical formula that indicates the kinds of atoms and the number of each kind in a molecule of a compound. Cf. empirical formula, structural formula. [1900 05] * * * …   Universalium

  • molecular formula — noun Date: 1869 a chemical formula that gives the total number of atoms of each element in each molecule of a substance compare structural formula …   New Collegiate Dictionary

  • molecular formula — molec′ular for′mula n. chem. a chemical formula that indicates the kind and number of atoms in a molecule of a compound • Etymology: 1900–05 …   From formal English to slang

  • molecular formula — /məlɛkjələ ˈfɔmjələ/ (say muhlekyuhluh fawmyuhluh) noun the formula of a chemical compound showing the number and kind of atoms present in the molecule, but not their arrangement …  

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