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    Hello all (especially big hello to EierVonSatan ),

    The question is about transition elements and has a image - read it here

    I have absolutely no clue whatsoever how to tackle it,
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    (Original post by qazwsxedc)
    Hello all (especially big hello to EierVonSatan ),

    The question is about transition elements and has a image - read it here

    I have absolutely no clue whatsoever how to tackle it,
    Would it not be the negatively charged oxygen and a nitrogen atom? Dative covalent bond is where both electrons being shared come from the same atom. Nitrogen has a lone pair, and the negatively charged oxygen has a pair it can use to bond with.
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    (Original post by cptbigt)
    Would it not be the negatively charged oxygen and a nitrogen atom? Dative covalent bond is where both electrons being shared come from the same atom. Nitrogen has a lone pair, and the negatively charged oxygen has a pair it can use to bond with.
    Your right cptbigt, thats the answer the mark scheme gave ,

    I understand that the nitrogen atom can donate a lone-pair of electrons,

    however, how can the oxygen ion donate a lone-pair of electron - i cannot even seem to figure out how it would bond to a central transition ion???
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    (Original post by qazwsxedc)
    Your right cptbigt, thats the answer the mark scheme gave ,

    I understand that the nitrogen atom can donate a lone-pair of electrons,

    however, how can the oxygen ion donate a lone-pair of electron - i cannot even seem to figure out how it would bond to a central transition ion???
    When oxygen forms two bonds, such as C=O, it has 2 lone pairs around it. But in your example, oxygen has only formed 1 bond, and has 3 lone pairs around it instead. It can then donate a lone pair, to form the dative covalent bond and end up with 4 around it like normal.
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    (Original post by cptbigt)
    When oxygen forms two bonds, such as C=O, it has 2 lone pairs around it. But in your example, oxygen has only formed 1 bond, and has 3 lone pairs around it instead. It can then donate a lone pair, to form the dative covalent bond and end up with 4 around it like normal.
    Crystal clear - but what happens to the other two lone-pairs?
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    (Original post by qazwsxedc)
    Your right cptbigt, thats the answer the mark scheme gave ,

    I understand that the nitrogen atom can donate a lone-pair of electrons,

    however, how can the oxygen ion donate a lone-pair of electron - i cannot even seem to figure out how it would bond to a central transition ion???
    The negative charge of oxygen ion means it has gained an extra electron, so it can dative covalent to the Ni2+ which has lost electrons, hence the positive charge.

    The LP on nitrogen can obviously does this as well.
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    (Original post by qazwsxedc)
    Crystal clear - but what happens to the other two lone-pairs?
    The two lone pairs will just remain around the oxygen like it does in other compounds (I think anyway)
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    (Original post by qazwsxedc)
    Crystal clear - but what happens to the other two lone-pairs?
    Oxygen usually form two bonds, and left with two lone pairs, that is like a stable state for oxygen usually. so by forming the complex, it goes back to having two lone pairs, hence get stabilized.
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    (Original post by cptbigt)
    The two lone pairs will just remain around the oxygen like it does in other compounds (I think anyway)
    Thanks cptbigt, I begin to understand

    (cheers shengoc, explanation is clear )
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    Dont forget that there is no difference between the oxygens in the EDTA ion. So questions about whether it is the C=O oxygen or the C-O- oxygen are irrelevant. The CO2(-) group has delocalisation and both oxygens are identical.

    EDTA forms a clathrate around metal ions - it is a hexadentate ligand (donates six lone pairs) which is what makes it so effective. The structure is octahedral around the metal ion.

 
 
 
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