Wed December 06, 2017 By: Anirbanbag81

But in this case, B is sp2 hybridised without any lone pair, so angle must be same i.e 120°, for all of them

Expert Reply
Thu December 07, 2017
In BX3, B atom is sp2 hybridized, hence it is a trigonal planar molecule with bond angle 120o
But this is not the case because the X halides are of different electronegativity, therefore, the bond angle will deviate.The electronegative atoms are pulled the bond pair towards them, hence more electronegative more attraction of the bond pair of electrons towards them hence less the bond angle.
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