https://doi.org/10.1351/goldbook.C01205
This term is sometimes applied to an @[email protected] which proceeds via an intermediate species having a lifetime longer than a few rotational periods, in contrast to a @[email protected] However, in view of the danger of confusion with a reaction occurring in more than one step (a @[email protected] ) this usage is not to be recommended; it is better to use the terms [email protected]@ mechanism or @[email protected]