In MarvinSketch, it is possible to use coordinate bonds to represent coordination compounds (ferrocenes, metallocenes).
The coordinate bond type can represent the connection between an atom and a group of atoms. The coordinate bond has the following types of representation:
A single bond
An arrow between two atoms
A dashed line between an atom and a group of atoms
On the Bonds Tab of the Preferences windows, you can change the default line type of the coordinate bonds.
To draw a coordinate bond between two atoms, choose the coordinate bond from the bond list and draw the bond by specifying the required direction.
To draw a coordinate bond between an atom and a group of atoms, follow the steps below.
Select the atoms to be represented at one end of the coordinate bond by a multi-center.
Choose Structure > Add > Multi-center from the main menu or Add > Multi-center from the contextual menu. A multi-center represented by an * (asterisk) will be added. If you move the cursor to the multi-center the represented atoms are highlighted (blue circle around the atom labels).
Draw a coordinate bond from the multi-center and edit the other end of the bond if required. The asterisk representing the multi-center disappears after the bond has been drawn.
Repeat steps 2-4 to draw further multi-centers and coordinate bonds if required.
Several examples are collected in the Insert > Template Library > Organometallics template library.