Structural Chemistry Tutorial Page
Trigonal Bypyramidal (AX5)
This is an example of a trigonal bypyramidal molecule. There is a central
atom surrounded by 5 adjacent atoms. Three of these adjacent atoms
exist on the equatorial plane, and 2 are on the axial plane. Denote
the atoms on the equatorial plane X1, the atoms on the axial plane X2, and
the central atom as A. In a perfect trigonal bypyramidal molecule, the
angles formed by X1-A-X1, are 120 degrees; the angles formed by X2-A-X1
are 90 degrees. For example, in phosphorus pentafluoride, PF5, the
F1-P-F2 angle is 90 degrees, and the F1-P-F1 angle is 120 degrees. Not all
trigonal bypyramidal molecules are this ideal. For example, sulfur oxide
tetrafluoride, SOF4, has a F1-S-O angle of 125 degrees, and a F1-S-F1
angle of 110.
To zoom, hold "Shift", and hold the left mouse button
moving it across the image. To rotate the molecule manually, hold the
left mouse button and drag it across the picture.
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