Coordination Number 2

The linear [Ag(NH3)2]+ ion

Although [Ag(en)]ClO4 involves a normally bidentate ligand, in this case the structure is polymeric and the silver ion still retains a CN=2 with the N atoms (from different ligands) at ~180 degrees to each other.

Coordination Number 3

Trigonal planar - D3h

[Cu(CN)3]2-

[CuBr(PNP)] where PNP= (2,6-bis[(di-tert-butylphosphino)methyl]pyridine)

To help view more easily, the H atoms are turned off.

Trigonal pyramid

T-shaped

[Cu(PNP)]SbF6 where PNP= (2,6-bis[(di-tert-butylphosphino)methyl]pyridine)

To help view more easily, the H atoms are turned off.

Coordination Number 4

Tetrahedral

CoCl2pyr2

Square Planar

cisplatin - cis-PtCl2(NH3)2

The cis- isomer is a powerful anti-cancer drug whereas the trans- is inactive.

Coordination Number 5

Square pyramid

Trigonal Bipyramid

[Ni(CN)5]3-

Coordination Number 6

Hexagonal planar

Trigonal prism

tris(cis-1,2-diphenylethene-1,2-dithiolato)rhenium

The ReS6 geometry is perfectly trigonal prismatic.

Octahedral

Hexol

The first 'truly' inorganic complex to be resolved into its optical isomers.

[Co(en)3]Cl3

mirror images

The classic example of optical isomerism in octahedral coordination complexes (H atoms not shown).
D isomer
L isomer

[CoCO3(NH3)5]+


Coordination Number 7

Capped octahedron (C3v)

K3[NbOF6]

Capped trigonal prism (C2v)

[V(III)(Hedta)(H2O)]H2O

Pentagonal Bipyramid (D5h)

bis-(tert-butylacac)2(DMSO)di-oxoUranium

The UO7 geometry fits a pentagonal bipyramid.

Coordination Number 8

Dodecahedron (D2d)

[Zr(acac)2(NO3)2]


[Zr(C2O4)4]4- is reported to have this shape as well.

Cube (Oh)

Square antiprism (D4d)

U(acac)4

Hexagonal bipyramid (D6h)

UO2(OAc)3

Coordination Number 9

Three-face centred trigonal prism (D3h)

Hydrated salts of the lanthanide elements eg Eu(H2O)9]3+

Coordination Number 10

Bicapped square antiprism (D4d)

Tetrakis(nitrato-O,O')-bis(triphenylphosphine oxide) cerium(IV)


Another example is [Ce(NO3)5]2-

Coordination Number 11

All-faced capped trigonal prism (D3h)

This is not a common stereochemistry.
In aqua-(12-crown-4)-tris(nitrato-O,O')-cerium(III) (12-crown-4) solvate and (15-crown-5)-tris(nitrato-O,O')-cerium(III) the Cerium ion is 11 coordinate.

Coordination Number 12

cuboctahedron (Oh)

Ceric ammonium nitrate -(NH4)2Ce(NO3)6

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Created and maintained by Prof. Robert J. Lancashire,
The Department of Chemistry, University of the West Indies,
Mona Campus, Kingston 7, Jamaica.
Created March 1996. Links checked and/or last modified 5th March 2014.
URL http://wwwchem.uwimona.edu.jm/courses/IC10Kcnpics.html