https://doi.org/10.1351/goldbook.B00673
For a structure containing the grouping R3C–C(Y)=X (with identical or different groups R) the @C01258@ in which the @T06406@ is such that X is @A00402@ to one of the groups R, and, in a @N04134@, the double bond C=X bisects one of the R–C–R angles. In this @C01258@ the bond C–Y @E01884@ one of the C–R bonds. The other @C01258@, in which X is @S06231@ to one of the groups R, is called an @E01885@.
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