Question #b496f

1 Answer
Feb 15, 2014

The molecular geometry of XeF₂ is linear.

To determine the geometry, we must draw the Lewis structure. We first draw a trial structure F-Xe-F, in which every atom has an octet, but this accounts for only 20 valence electrons. We must use
8 + 2×7 = 22 valence electrons, so we place the two extra electrons on the central atom (Xe). The Lewis structure becomes

Now we use VSEPR theory to predict the electron pair geometry. XeF₂ is classed as an AX₂E₃ molecule. The five electron pairs point towards the corners of a trigonal bipyramid. The bulky lone pairs occupy the equatorial positions and the Xe-F bonds point toward the axial locations.

Although the electron pair geometry is trigonal bipyramidal, we don’t really “see” the lone pairs. We "see" the atoms and the bonds between them. This is called the molecular geometry. XeF₂ therefore has a linear geometry with a bond angle of 180°.