The families of shapes are given below for molecules (or ions) that have a total of five or six electron pair domains about the central atom, AND some of these are non-bonding domains.
Recall that molecular shape is a descriptor of the positions of the outer atoms in a molecule. Thus the shape descriptor of molecules or ions which have octahedral and trigonal pyramidal arrangements of bonding electron pair domains is different when one or more of the domains is nonbonding.
Nonbonding electron pairs occupy more space closer to the central atom than bonding electron pairs. This has the result that in molecules which are asymmetric (AX4E, AX3E2, AX5E) that the AX bond angles are smaller then when the bonding and non-bonding pairs are symmetrically distributed about A.
Recall that molecular shape is a descriptor of the positions of the outer atoms in a molecule. Thus the shape descriptor of molecules or ions which have octahedral and trigonal pyramidal arrangements of bonding electron pair domains is different when one or more of the domains is nonbonding.
Nonbonding electron pairs occupy more space closer to the central atom than bonding electron pairs. This has the result that in molecules which are asymmetric (AX4E, AX3E2, AX5E) that the AX bond angles are smaller then when the bonding and non-bonding pairs are symmetrically distributed about A.
AX6
octahedral
AX5E
square pyramid
AX4E2
square planar
octahedral
AX5E
square pyramid
AX4E2
square planar
AX5 trigonal bipyramid  AX4E see-saw  AX3E2 t-shaped  AX2E3 linear  |