The central atom in NH₃, which is nitrogen, undergoes sp3 hybridization. During the formation of NH₃, one 2s orbital and three 2p orbitals of nitrogen combine to form four hybrid orbitals having equivalent energy, which is then considered as an sp3 type of hybridization. The three half-filled sp3 orbitals of nitrogen form bonds to hydrogens three atoms, while the fourth sp3 orbital is a nonbonding pair of hybridized orbital and is normally used for holding the lone pair. The molecular geometry of NH₃ is trigonal pyramidal or distorted tetrahedral due to the presence of a lone non-bonding pair which usually exerts a repulsive force on the bonding orbitals. The bond angle in NH₃ is 107° .