PLANNER TRIANGLE MOLECULE:
Boron Flouride (BF3),Sulphurdioxide (SO2) and Ethene (C2HA) are the examples of planner triangle molecules.
STRUCTURE OF BF3
BF3 is a triangle shape molecule with bond angle of 120°. There are three active electron pairs around the Boron atom.
In terms of EPRT, three pairs of electrons are so adjusted that repulsion is minimum, which is achieved by placing each F-atom at the corners of Equivalent triangle at 120° bond angle shape:
In terms of HOM, Boron atom undergoes sp2 hybridization producing three sp2 hybrid orbitals:
B (ground state) : 1S2 , 252 , 2px1
B (excited state) : 1S2 , 252 , 2px1, 2py1
After hybridization three sp2 hybrid orbital are formed.
These three hybrid orbitals overlap with pz orbital of F-atom producing sigma-bond giving BF3.