The Bond SmartSlide

Once you have modified a parameter using the SmartSlide, the OK button must be pressed before any of the changes made on any SmartSlide are actually applied to the molecule. Clicking the close box will discard any changes (as will selecting the Cancel button).

The Bond SmartSlide is illustrated below. The initial bond length value is set to the distance between the selected pair of atoms, and the type of bond existing between them is indicated. The SmartSlide provides access to all the possible bond types.

The interatomic distance is dynamically adjusted by moving the slider along the scale. Values may also be directly entered in the text box.

You can change the bond type by clicking one of the bond type radio buttons without affecting the valence on the atoms from which the bonds are removed.

Note that the Bond SmartSlide is also used to add bonds between unbonded atoms. Simply click on the two atoms to be bonded as usual. When the SmartSlide opens, click on the type of bond desired, and the bond will be created. Similarly, to remove a bond, select the two atoms you want to unbond, and then select the None radio button in the dialog.

bond_ss.tif
The Bond SmartSlide

This dialog can be used to add, remove, and change bond lengths.

The Displacement fields specify how attached groups are handled as the bond distance changes:

The following figure illustrates the effects of different combinations of these choices:

bond_bef.tif
Original
bond_f_ta.tif
1=Fixed, 2=Translate Atom
bond_f_tg.tif
1=Fixed, 2=Translate Group
bond_tg_tg.tif
1,2=Translate Group

Bond Length Modification Options

All three of these structures result from lengthening the bond distance between the two selected C atoms (to the same value in all three cases). In the left picture, atom 1 was held fixed, and atom 2 was set to Translate Atom. Compare this to the middle picture which also held atom 1 fixed and set atom 2 to Translate Group. The upper methyl group stays fixed in the first case, while the 1-2-R bond angle remains unchanged in the center case. The right picture sets both atoms to Translate Group, probably the most common choice for a case like this one.