Question

(10 pts) What angle would you predict for the (smallest) F – Cl – F bond angle in CIF: (chlorine trifluoride) based on your knowledge of VSEPR and the Lewis structure of C1F3? Bond angle/deg. =

Answer 1

has an electronic geometry of trigonal bipyramid type, with the two lone pairs at the equatorial position, the molecular geometry becomes T-shape. Let us discuss its Lewis structure as below-

CIF:

The has two types of bonds,

CIF:

Bond angle	Value
$\measuredangle F_{a}-Cl-F_{e}$	$90^{\circ}$ expected, $86^{\circ}$ actual
$\measuredangle F_{a}-Cl-F_{a}$	$180^{\circ}$ expected, $172^{\circ}$ actual.

F: LE axial a = 86 degrees CI F: Cl F. • equatorial =86 degrees :F: F axial The Lewis structure of CIF3, (A or B), the central Cl atom is sp3d hybridized and two different bond angles will be there. Due to the lone-pair bond pair repulsion, the axial C-F bonds is forced to bend and due to this, the < Fa-C-Fa becomes = 172 degree(from the standard 180 degree) and the < Fa-C-Fe = 86 degree from the standard 90 degree angle).

Hence, the smallest $\measuredangle F_{a}-Cl-F_{e}$ bond angle is $90^{\circ}$ (expected) , $86^{\circ}$ actual (due to the shrinkage of the bond angle due to lone-pair - bond-pair repulsion).