The repulsion is in the order: lp-lp > lp-bp > bp-bp.
In PF3, there is a lp-lp repulsion, the angle of PF3 will be less than BF3.
The geometry of BF3 is trigonal planar while NH3 is tetrahedral
The sequence will therefore be, BF3> NH3>PF3
I3- is a linear molecule therefore, the angle is 180 degree.
The overall order will be I3- > BF3> NH3>PF3
The bond angles \( b_1, b_2, b_3 \) in the above structure are respectively in \( ^\circ \):
The correct order of bond enthalpy \(\left( kJ mol ^{-1}\right)\) is :
Covalent bonds can be characterized on the basis of several bond parameters such as bond length, bond angle, bond order, and bond energy (also known as bond enthalpy). These bond parameters offer insight into the stability of a chemical compound and the strength of the chemical bonds holding its atoms together.
For example, The H—H bond enthalpy in hydrogen is 435.8 kJ mol-1. \
Bond order of H2 (H —H) =1
Bond order of 02 (O = O) =2
Bond order of N2 (N = N) =3
Read More: Chemical Bonding and Molecular Structure