Planner Triangle Molecule:
BF3 (Boron triflouride), SO3, CZHA are the examples of planner triangle molecule.
Structure of BF3
BF3 is a triangle shape molecule with bond angle 120º. There are three active electron pairs amount the Boron action.
i. BF3 is a trigonal shape molecule with bond angle 120°. There are three active electron pairs around the Boron atom.
ii. In terms of electron pair repulsion theory, three pairs of electrons are so adjusted by placing each F atom at the corners of equivalent triangle at 120° bond angle
iii. In terms of hybrid orbital theory, B atom undergoes Sp2 hybridization producing three Sp2 hybrid orbitals.
B (ground) —> 1s2, 2s2, 2p1x
B (excited) —> 1s2, 2s2, 2p1x, 2p1y
These three hybrid orbitals overlap with Px orbital of F atom producing sigma bond giving BF3.