The Foundations of Chemistry

344 CHAPTER 8: Molecular Structure and Covalent Bonding Theories

TABLE 8-4 A Summary of Electronic and Molecular Geometries of Polyatomic Molecules and Ions

Regions
of High Hybridization at
Electron Central Atom Hybridized Orbital
Densitya Electronic Geometry (Angles) Orientation Examples Molecular Geometry

BeCl 2 linear

HgBr 2 linear

sp

(^2) (180°) CdI 2 linear
CO 2 b linear
linear C 2 H 2 c linear
BF 3 trigonal planar
BCl 3 trigonal planar
NO 3
e trigonal planar
3 sp^2 SO
(120°)^2 d,e angular (AB^2 U)
NO 2
d,e angular (AB 2 U)
C 2 H 4 f planar (trig. planar
trigonal planar at each C)
CH 4 tetrahedral
CCl 4 tetrahedral
NH 4  tetrahedral
SO 42
tetrahedral
4 sp^3 CHCl
(109.5°)^3 distorted tet.
NH 3 d pyramidal (AB 3 U)
SO 32
d pyramidal (AB 3 U)
H 3 Od pyramidal (AB 3 U)
tetrahedral H 2 Od angular (AB 2 U 2 )
PF 5 trigonal bipyramidal
SbCl 5 trigonal bipyramidal
sp^3 d
(^5) (90°, 120°, 180°) SF 4 d seesaw (AB 4 U)
ClF 3 d T-shaped (AB 3 U 2 )
XeF 2 d linear (AB 2 U 3 )
I 3
d linear (AB 2 U 3 )
trigonal bipyramidal
SF 6 octahedral
SeF 6 octahedral
PF 6
octahedral
6 sp^3 d^2 BrF
(90°, 180°)^5 d square pyramidal
(AB 5 U)
XeF 4 d square planar
(AB 4 U 2 )
octahedral
aThe number of locations of high electron density around the central atom. A region of high electron density may be a single bond, a double bond, a triple bond, or an
unshared pair. These determine the electronic geometry, and thus the hybridization of the central atom.
bContains two double bonds.
cContains a triple bond.
dCentral atom in molecule or ion has unshared pair(s) of electrons.
eBonding involves resonance.
fContains one double bond.
A
A
A
A
A