chemfig

Reaction schemes

7 Branching¶

So far, only linear reaction schemes have been treated. Branched schemes are also possible and this is where compound names play a key role. When a name is preceded by “@” in the argument between brackets of the \arrow command, it means that the compound already exists. Several scenarios are possible:

• (@n1--n2): the arrow will leave from the existing compound “n1” and the scheme will continue following the arrow, thus creating a branch;

• (@n1--@n2): the arrow is drawn between two existing compounds, no matter whether they are already defined or whether they will later in the reaction scheme: therefore this syntax can be placed anywhere in the code of the reaction scheme;

• (n1--@n2): this syntax is not permitted;

In the following example, 3 branches are made, a first one from “B”, a second one from “D” and a last one from “X”. Finally one more arrow connects two existing compounds: “XX” and “D”:

One may wish to have “Y” and “XX” on the same horizontal line. To achieve this, a horizontal invisible bond is drawn between “Y” and “XX”; the scheme is completed with a final arrow between the two existing compounds “XX” and “D”: