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Molecular Examples

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        at (Bookshelves/Inorganic_Chemistry/Supplemental_Modules_and_Websites_(Inorganic_Chemistry)/Coordination_Chemistry/Structure_and_Nomenclature_of_Coordination_Compounds/Coordination_Numbers_and_Geometry/Molecular_Examples), /content/body/pre/@function, line 1, column 1

    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



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

    Trigonal pyramid



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

    Coordination Number 4



    Square Planar

    cisplatin - cis-Pt(NH3)2Cl2

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

    Coordination Number 5

    Square pyramid

    Trigonal Bipyramid


    Coordination Number 6

    Hexagonal planar

    Trigonal prism


    The ReS6 geometry is perfectly trigonal prismatic.



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


    mirror images

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


    Coordination Number 7

    Capped octahedron (C3v)


    Capped trigonal prism (C2v)


    Pentagonal Bipyramid (D5h)


    The UO7 geometry fits a pentagonal bipyramid.

    Coordination Number 8

    Dodecahedron (D2d)


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

    Cube (Oh)

    Square antiprism (D4d)


    Hexagonal bipyramid (D6h)


    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

    Contributors and Attributions

    • Prof. Robert J. Lancashire (The Department of Chemistry, University of the West Indies)

    Molecular Examples is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by LibreTexts.

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