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Monday, January 18, 2021

Dipole moment of P(CH3)2(CF3)2 molecule is zero while dipole moment of P(CH3)2(CF)3 molecule is non zero why?

According to bent’s rule more electronegative atom or group attached those hybrids orbital have minimum s-character.

There is sp3d (Sp2+pd) hybridization trigonal bipiramidal(TBP) geometry in P(CH₃)₂(CF₃)₂molecule. we known that axial orbital (pd) have no s-character so –CF₃ groups are attached with axial positions while –CH₃ groups attach with equatorial (Sp2) position. Hence net dipole moment becomes zero. While in case of P(CH₃)₂(CF)₃ molecule one of the –CF₃ group is also present at equatorial position hence there is net dipole moment.