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