Question

XeOF4 is a noble gas compound. Determine:

a) Its structure using VSEPR rules

b) Assign its point group

c) Determine the symmetry of the normal modes of vibration.

d) Also, identify which representations are attributable to translation and rotation.

Answer 1

(A ) XeOF₄

Central atom:	Xe
Xe contributes:	8 e−
O contibutes:	2 e−
4 x F contribute:	4 e−
Total VSE:	14
Total VSEP:	7
1 x double bond	− 1 pair
Revised Total:	6
Geometry:	Square pyramidal (based on octahedral)

(B)  

XeOF4 is a sqauare pyrapidal compound with 4F occupying equatorial position and double bonded oxygen and loan pair axially oriented, so the symmetry elements are C4(primciple axis of symmetry) and C2 both passing through Xe vertically containing loan pair-Xe-double bonded oxygen.

There are also sigma planes from corner containing F-Xe-double bonded oxygen and bisecting axial loan pair of Xe.

point group of XeOF4 is C_4v.

(c)

Thus normal modes of vibration are having A₁, B₁ and E symetry

(D)  From the character table it is clear that A₁ mode is attributable to translation as given by linear function z

From the character table it is clear that B₁ mode is attributable to rotation as R_z is given.

From the character table it is clear that E mode is attributable to both translation and rotation as given as (x,y) and (R_x , R_y )