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2 definitions found
 for ((-CH2-
From The Collaborative International Dictionary of English v.0.48 :

  Methylene \Meth"yl*ene\, n. [F. m['e]thyl[`e]ne, from Gr. ? wine
     + ? wood; -- a word coined to correspond to the name wood
     spirit.] (Chem.)
     A divalent hydrocarbon radical, -CH2-, not known in the
     free state, but regarded as an essential residue and
     component of certain derivatives of methane; as, methylene
     bromide, CH2Br2; -- formerly called also methene.
     [1913 Webster]
  
     Methylene blue (Chem.), an artificial dyestuff consisting
        of a complex sulphur derivative of diphenyl amine; --
        called also pure blue.
        [1913 Webster]

From The Collaborative International Dictionary of English v.0.48 :

  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]

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