Question
Describe the molecular shape of BrF3 on the basis of VSEPR theory.
Solution
The central atom Br has seven electrons in the valence shell. Three of these will form electron-pair bonds with three fluorine atoms leaving behind four electrons. Thus, there are three bond pairs and two lone pairs. The hybridization sp3d.
Fig. Molecular shape of BrF3
According to VSEPR theory, these will occupy the corners of a trigonal bipyramid. The two lone pairs will occupy the equatorial positions to minimise lone pair-lone pair and the bond pair-lone pair repulsions which are greater than the bond pair-bond pair repulsions. In addition, the axial fluorine atoms will be bent towards the equatorial fluorine in the order to minimise the lone pair-lone pair repulsions. The shape would be that of a slightly bent‘T’.
Fig. Molecular shape of BrF3
According to VSEPR theory, these will occupy the corners of a trigonal bipyramid. The two lone pairs will occupy the equatorial positions to minimise lone pair-lone pair and the bond pair-lone pair repulsions which are greater than the bond pair-bond pair repulsions. In addition, the axial fluorine atoms will be bent towards the equatorial fluorine in the order to minimise the lone pair-lone pair repulsions. The shape would be that of a slightly bent‘T’.
