Valence Shell Electron Pair Repulsion

Steric Number (S.N.)

number of bonded atoms to the central atom + lone pairs

Coordination number (C.N.)

The number of atoms bound to the central atom

electron geometry

the geometry by treating electron pairs like another atom (S.N.)

Molecular geometry

geometry where you don’t see the electron pairs

Steric number 2 - No lone pair

AX2

Steric number 2 - electron geometry

linear

Steric number 2 - molecular geometry

linear

Steric number 2 - bond angle

180

Steric number 3 - no lone pair

AX3

Steric number 3 - electron geometry

triagonal planer

Steric number 3 - molecular geometry

trigonal planer

Steric number 3 - bond angle

120

Steric number 3 - 1 lone pair

AX3E

Steric number 3 - 1 lone pair - electron geometry

trigonal planer

Steric number 3 -1 lone pair - molecular geometry

Bent

Steric number 3 -1 lone pair - bond angle

< 120 (less than)

Steric number 4- no lone pair

AX4

Steric number 4- electron geometry

tetrahedral

Steric number 4 - molecular geometry

tetrahedral

Steric number 4 - bond angle

109.5

Steric number 4 - 1 lone pair

AX4E

Steric number 4 - 1 lone pair - electron geometry

tetrahedral

Steric number 4 - 1 lone pair - molecular geometry

trigonal pyramidal

Steric number 4 - 1 lone pair - bond angle

< 109.5

Steric number 4 - 2 lone pair

AX2E2

Steric number 4 - 2 lone pair - electron geometry

tetrahedral

Steric number 4 - 2 lone pair - molecular geometry

Bent

Steric number 4 - 2 lone pair - bond angle

< 109.5

Steric number 5 - no lone pairs

AX5

Steric number 5 - electron geometry

trigonal bipyramidal

Steric number 5 - molecular geometry

trigonal bipyramidal

Steric number 5 - bond angle

90 & 120

Steric number 5 - 1 lone pair

AX4E

Steric number 5 - 1 lone pair - electron geometry

trigonal bipyramidal

Steric number 5 - 1 lone pair - molecular geometry

see-saw

Steric number 5 - 1 lone pair - bond angle

< 90 & <120

Steric number 5 - 2 lone pair

AX3E2

Steric number 5 - 2 lone pair - electron geometry

trigonal bipyramidal

Steric number 5 - 2 lone pair - molecular geometry

T shaped

Steric number 5 - 2 lone pair - bond angle

<90

Steric number 5 - 3 lone pair

AX2E3

Steric number 5 - 3 lone pair - electron geometry

trigonal bipyramidal

Steric number 5 - 3 lone pair - molecular geometry

linear

Steric number 5 - 3 lone pair - bond angle

180

Steric number 6 - no lone pair

AX6

Steric number 6 - electron geometry

octahedral

Steric number 6 - molecular geometry

octahedral

Steric number 6 - bond angle

90

Steric number 6 - 1 lone pair

AX5E

Steric number 6 - 1 lone pair - electron geometry

octahedral

Steric number 6 - 1 lone pair - molecular geometry

square pyramidal

Steric number 6 - 1 lone pair - bond order

<90

Steric number 6 - 2 lone pair

AX4E2

Steric number 6 - 2 lone pair - electron geometry

octahedral

Steric number 6 - 2 lone pair - molecular geometry

square planer

Steric number 6 - 2 lone pair - bond angle

90

S.N. 2 - Hybridization

sp

S.N. 3 - Hybridization

sp2

S.N. 4 - Hybridization

sp3

S.N. 5 - Hybridization

sp3d

S.N. 6 - Hybridization

sp3d2

sp - generic formulas

AX2 , AXE

sp2 - generic formulas

AX3, AX2E, AXE2

sp3 - generic formulas

AX4, AX3E, AX2E2, AXE3

sp3d - generic formulas

AX5, AX4E, AX3E2, AX2E3

sp3d2 - generic formulas

AX6, AX5E, AX4E2