When all three atoms at the corners are identical, the molecule belongs to point group C3v.

In organic chemistry, molecules which have a trigonal pyramidal geometry are sometimes described as sp3 hybridized.

The nitrogen in ammonia has 5 valence electrons and bonds with three hydrogen atoms to complete the octet.

This would result in the geometry of a regular tetrahedron with each bond angle equal to arccos(−⁠1/3⁠) ≈ 109.5°.

In ammonia the trigonal pyramid undergoes rapid nitrogen inversion.