Which of the following has an octahedral electron geometry? (A) ICl+2, (B) ICl2, (C) IF7, (D) ICl4

1 Answer
Aug 3, 2017

Apparently, ICl4. It uses sp3d2 hybridization (i.e. octahedral electron geometry), for a square planar molecular geometry (i.e. two lone pairs).


Well, using the electron-counting method,

A)

ICl+2 has...

7+141=20 valence electrons.

And so, we form the skeletal structure and distribute valence electrons to get a bent molecular geometry:

The sp3 hybridization here requires zero d orbitals, but there exist two lone pairs around I.

B)

ICl2 has...

  • 7 valence electrons from I
  • 7×2=14 valence electrons total from Cl
  • +1 valence electrons due to the charge

7+14+1=22 valence electrons.

And so, we form the skeletal structure and distribute valence electrons to get a linear molecular geometry:

The sp3d hybridization here (for 1+3+1=five electron groups) requires one d orbital, but there exist three lone pairs around I.

C)

IF7 has...

  • 7 valence electrons from I
  • 7×7=49 valence electrons total from F

7+49=56 valence electrons.

And so, we form the skeletal structure and distribute valence electrons to get a pentagonal bipyramidal molecular geometry:

The hybridization here (for seven electron groups) will be sp3d3. Specifically, it will involve the linear combination of...

s+pz+(px,py)+dz2+(dx2y2,dxy)sp3d3

It requires three d orbitals, but there exist zero lone pairs around I.

D)

ICl4 has...

  • 7 valence electrons from I
  • 7×4=28 valence electrons total from Cl
  • 1 valence electron from the charge

7+28+1=36 valence electrons.

And so, we form the skeletal structure and distribute valence electrons to get a square planar molecular geometry:

The hybridization here (for six electron groups) will be sp3d2.

It requires two d orbitals, and there exist two lone pairs around I.