Bond Properties include bond multiplicity, bond style and bond color.

To change the multiplicity of a bond,

Click the , or , or  button in the Structure Editor window and then click the bond you want to change.

To change the color or optical orientation of a bond, use the Bond Properties dialog window.

To open the Bond Properties window:

• Click the Bond Properties  button in Structure Editor and then click the bond you want to change. The Bond Properties dialog window will then appear.
• Or restore defaults, and then double-click on the bond you want to change. The Bond Properties dialog window will then appear.

Mass Frontier automatically recognizes aromatic bonds in an appropriate six-membered ring or in polyaromatic structures. However, if unusual semiaromatic or aromatic resonance structures are required, the aromatic bond can be forced to selected bond(s) by checking the Force Aromaticity check box.