Trigonal Bipyramidal
The Trigonal Bipyramidal is a molecular shape where there are 5 bonds attached to a central atom. There are two bond angles for this shape. The first one is 90 degrees and the second one is 120 degrees. The shape is non-polar since it is symmetrical. There are no lone pairs attached to the central atom. Here are some examples of Trigonal Bipyramidal shape:
Phosphorous Pentachloride
Phosphorous Pentaflouride
What contributes to this shape?
The only thing that contributes to this shape are the five bonds which the central atom is attached to. There are no lone pairs of electrons which would repel with the surrounding atoms and provide a different bond angle and shape. Since there are only 5 bonds attached to it and no lone pairs, the bond angles tend to be 90 degrees and 120 degrees since the bonds won't bend.