In the following structures carbon atoms are dark gray and hydrogens are cyan. The molecules can be rotated by clicking on the structure and dragging the mouse. Holding the shift key during this operation allows zooming. If all four models are not displayed, it may be necessary to reload the page by clicking the reload button.
By viewing and manipulating these structures and their mono, di & tri-substituted derivatives, you should convince yourself that the tetrahedral configuration has only a single possible structure for each substitution pattern, whereas the square planar and square pyramidal configurations have two possible disubstitution structures and the triangular pyramidal configuration would have two monosubstituted, two disubstituted & two trisubstituted structures (not all of these are shown here). The unique apical hydrogen in the triangular pyramidal configuration is colored a gray-blue.