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    How do you tell if a complex ion has a tetrahedral shape or that of square planar?
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    square planers have lone pairs on its central ion i think the central ion would have 4 atoms attached with 2 lone pairs
    the tetrahedral has also 4 atoms attached to its central ion but has no lone pairs
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    (Original post by CrystalSalvatore)
    square planers have lone pairs on its central ion i think the central ion would have 4 atoms attached with 2 lone pairs
    the tetrahedral has also 4 atoms attached to its central ion but has no lone pairs
    Why is [RhCl4]
    2–
    Tetrahedral?
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    You have to consider the number of electron domains the molecule has and which shape would allow the most stability (least repulsion). A molecule with 6 electron domains (2 of which are lone pairs and 4 of which are bonds to something else) will take on the square planar shape. A molecule with 4 electron domains will take on the shape of a tetrahedral. In tetrahedral shape, the bond angles are approximately 109.5 degrees, while when you try to visualize a square planar, the bond angles are only 90 degrees. The molecule wants to have the largest angle possible between each atoms so it will take on the tetrahedral shape.
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    (Original post by splle)
    You have to consider the number of electron domains the molecule has and which shape would allow the most stability (least repulsion). A molecule with 6 electron domains (2 of which are lone pairs and 4 of which are bonds to something else) will take on the square planar shape. A molecule with 4 electron domains will take on the shape of a tetrahedral. In tetrahedral shape, the bond angles are approximately 109.5 degrees, while when you try to visualize a square planar, the bond angles are only 90 degrees. The molecule wants to have the largest angle possible between each atoms so it will take on the tetrahedral shape.
    How do you know there are two lone pairs?
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    (Original post by geography1294)
    How do you know there are two lone pairs?
    Sorry, I didn't see your second question when I posted my answer. In my previous post I was just generalizing, not referring to the molecule in question.
    I am not 100% sure on this as I haven't fully learned about complex ions yet, but from the examples I've seen I believe that, to find the shape, you would simply look at the number of ligands and from there deduce the shape. Therefore for your molecule, since there are 4 coordinate bonds, the shape would be tetrahedral. I'm not absolutely certain though!
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    (Original post by geography1294)
    Why is [RhCl4]
    2–
    Tetrahedral?
    What level are you at? A-Level or undergraduate?
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    (Original post by geography1294)
    How do you tell if a complex ion has a tetrahedral shape or that of square planar?
    The transition metal complexes are fomed by lone pair coordination into empty orbitals in a level above the occupied d- orbitals.

    In other words a transition metal complex from the first row does not involve the 3d electons when forming complexes, BUT the electronic configuration of the 3d electrons influences the orbitals that are used for bonding.

    In general square planar complexes are not usually formed unless the transition metal ion has a d8 configuration (typical Ni2+).

    Most four coordinate complexes are tetrahedral.

    TLDR - there is no way of knowing but you can learn the trends.
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    (Original post by charco)
    The transition metal complexes are fomed by lone pair coordination into empty orbitals in a level above the occupied d- orbitals.

    In other words a transition metal complex from the first row does not involve the 3d electons when forming complexes, BUT the electronic configuration of the 3d electrons influences the orbitals that are used for bonding.

    In general square planar complexes are not usually formed unless the transition metal ion has a d8 configuration (typical Ni2+).

    Most four coordinate complexes are tetrahedral.

    TLDR - there is no way of knowing but you can learn the trends.
    d8 as in for eg 3d8?
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    (Original post by geography1294)
    d8 as in for eg 3d8?
    yup
 
 
 
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