sm_logo.gif (1738 bytes) Drawing Three Dimensional (3-D) Structures on Paper (continued)

         Incorporating three dimensional information into line structures.


ORANGE.GIF (334 bytes) All of the lines (bonds) that we have used so far in drawing structures have been "normal" lines. These normal lines are used to represent bonds that lies in the plane of the drawing surface (i.e the computer screen, the paper, the chalkboard, etc.) In order to represent bonds projecting out of this plane, we use "dashed" and "wedged" bonds.

Dashed bonds are used to represent bonds that project backward (behind the drawing plane).

Wedged bonds are used to represent bonds that project outward (in front of the drawing plane).

ORANGE.GIF (334 bytes) The three common types of bonds used in drawing chemical structures:

ORANGE.GIF (334 bytes) Thus, we can take a simple molecule such as methane and represent its tetrahedryl geometry using wedged and dashed bonds as follows:
ORANGE.GIF (334 bytes) Compare this to the molecular model: 
ORANGE.GIF (334 bytes) We can also use this convention to represent stereoisomers.
ORANGE.GIF (334 bytes) Take a look at the two stereoisomers of 2-bromobutane, which we looked at before.

Rotate the 3D models so that they match the line structures.

(S)-2-bromobutane

(R)-2-bromobutane

Note that it is possible to draw a number of different line structures representing different views of the same molecule (only two are shown below for each stereoisomer).


Copyright 1996 -1999, 2007 by Frank R. Gorga - All rights reserved.

Last Update: 12-Mar-2007