The molecular geometry of PCl3 (phosphorus trichloride) is trigonal pyramidal. This geometry arises because phosphorus has five valence electrons, and it forms three covalent bonds with chlorine atoms. The lone pair of electrons on the phosphorus atom repels the bonding pairs, causing the molecule to adopt a pyramidal shape.
In a trigonal pyramidal geometry, the three chlorine atoms are positioned at the base of the pyramid, while the lone pair of electrons occupies the apex. The bond angles in PCl3 are approximately 107 degrees, which is slightly less than the ideal tetrahedral angle of 109.5 degrees due to the repulsion from the lone pair.
This molecular geometry is important in understanding the chemical behavior and reactivity of PCl3, as it influences how the molecule interacts with other substances.