In Teil II *Operation of ChemFig* Abschnitt 9 *Connecting Distant Atoms* ist die Syntax des `?`-Hooks beschrieben:
> Fortunately the character `?` has an
> optional argument:
>
> ?[<name>,<bond>,<tikz>]
`?[<name>,<bond>,<tikz>]`
>
> where each field takes its default
> value if it is empty:
>
> - The `<name>` is the name of the hook: all alphanumeric characters
> (a…z, A…Z, 0…9) are allowed. The name
> is `a` by default. In the first
> occurrence of the hook with this name,
> only this field is used.
> - `<bond>` specifies how the atom with the current occurrence of the
> named hook is to be bonded to the atom
> with the first occurrence of the hook.
> There are two ways this can be done.
> First, this field can be an integer
> representing the desired bond type:
> 1=single bond, 2=double bond, etc.
> (See the table on page 5 for the bond
> codes.) Second, the field can be one
> of the bond character codes, provided
> that this character is between braces.
> - `<tikz>` will be passed directly to TikZ as we have seen with regular
> bonds.
Also einfach der `<tikz>`-Option die gewünschte Farbe überreichen:
\chemfig{
?
-[:195,,,,red]
-[:50,,,,red]
-[:80,,,,red]
-[:20,,,,red]
-[:-130,,,,red]
?[,,blue,ultra thick](
-[:10,,,,red]
-[:-10,,,,red]
-[:40,,,,red]
-[:-170,,,,red]
-[:-195,1.2,,,red]
)
}
![alt text][1]
[1]: http://texwelt.de/wissen/upfiles/chemfig-hook.png
