Reaction Tools

The default tool is the Straight arrow. Other arrow types can be selected from a sub-menu, after clicking on the black triangle in the lower-right corner of the button.

It is also a multifunctional tool, that draws graphical arrows, reaction operators, for example, + sign and arrow, and maps the atoms in the reaction.

Reaction arrow symbol

Reaction arrow type


Straight arrow


Two-headed arrow (Resonance arrow.)


Equilibrium arrow

Place a + Sign

Select the Reaction tool, then left-click on the canvas where you would like to place the + sign.

Placing an Arrow

Select the Reaction tool, then drag with it on the canvas where you would like to place the arrow. During the dragging, gray feedback shows the position of the newly forming arrow. Release the button to create the arrow.

If it is necessary the length and the direction of the arrow can be changed afterward.


Select the smart Reaction tool from the Tools toolbar, then press the left mouse button on the atom you would like to map, and drag to the other atom, which receives the same map number. (Golden brown feedback helps the process.) After releasing the mouse button, the atom map number appears on the lower-right corner of the selected atoms.