Shape of I3-

[Vanessa Chuang 4F]

For homework question 2E.13, we are asked to draw the shape of I3-. The resulting shape is an iodine as the central atom with 2 bonding pairs and 3 lone pairs. The answer to this is a linear shape. My question is do the 3 lone pairs on the central atom "cancel" each other out in order to make this a linear shape? Or is there some other reasoning?

[haileyramsey-1c]

In I3- there are three lone pairs around the central atom. The shape is linear because all three of the lone pairs are in the same plane (equatorial) which causes their dipole moments to cancel because they are of equal magnitude and in equally opposing directions.

[haileyramsey-1c]

In I3- there are three lone pairs around the central atom. The shape is linear because all three of the lone pairs are in the same plane (equatorial) which causes their dipole moments to cancel because they are of equal magnitude and in equally opposing directions.

[Tyler Angtuaco 1G]

I3- would have a square pyramidal electron arrangement. If you picture the lone pairs of electrons being in the farthest positions away from each other (because repulsion of electron clouds between lone pairs are strongest), one would be on the axial atom (top of the pyramid), and two pairs would be 180 degrees away from each other. The molecular shape would be linear since molecular shape only accounts for the position of the atoms.