What shape does an ammonia molecule have?

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Difference in molecular structure between ammonia/amines and quaternary ammonium ions — ammonia Ammonia and amines have a slightly flattened trigonal pyramidal shape with a lone pair of electrons above the nitrogen. In quaternary ammonium ions, this area is occupied by a fourth substituent.

The ammonia molecule (NH₃) has a trigonal pyramidal geometry.12

In this arrangement, the nitrogen atom sits at the apex of the pyramid, while the three hydrogen atoms form the base. This shape is a result of the four electron pairs surrounding the central nitrogen atom, which adopt a tetrahedral disposition. Three of these electron pairs are involved in bonding with hydrogen atoms, while the fourth is an unshared lone pair.123

Because lone pairs occupy more space than bonding pairs, they exert greater repulsion, which pushes the three hydrogen atoms closer together. Consequently, while a perfect tetrahedral angle is 109.5°, the H–N–H bond angle in ammonia is approximately 107°.3