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    I understand how we draw a molecule e.g CH3 as a tetrahedral with three different planes (dotted lines, straight lines and wedge-shaped). But why do we draw octahedral complexes with three planes, when there are only two? I asked this to my chemistry teacher and I don't think she had a clue what I meant... Is it just a convention?
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    I think theres still 3 diferent planes: atoms above, below and on the plane. (if you get that)

    I draw complexes the same as I would draw a tetrahedral molecule, with dotted lines, wedges and normal lines on the plane. I just usually draw a square and two lines up and down (dotted and wedged)
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    There are two planes; the one that we would recognise as the vertical (the molecule/ion above and below the metal ion) and then the plane that the other four ligands are in; the square (the plane perpendicular to the vertical plane previously mentioned).
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    Wooo, an excuse to get out the model kit!
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    (Original post by Superacid)
    There are two planes; the one that we would recognise as the vertical (the molecule/ion above and below the metal ion) and then the plane that the other four ligands are in; the square (the plane perpendicular to the vertical plane previously mentioned).
    Ahh ok, I was counting up and down as seperate planes
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    (Original post by Superacid)
    There are two planes; the one that we would recognise as the vertical (the molecule/ion above and below the metal ion) and then the plane that the other four ligands are in; the square (the plane perpendicular to the vertical plane previously mentioned).
    The ligands are in three dimensions, and they are drawn to represent 3D. The two up & down are in 1 dimension, the two pointing toward you and the two pointing away all exist in a 2 dimension plane. That's just what an octahedron looks like.
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    So the different type of line (wedged, dotted etc.) actually represents the dimensions rather than the plane ?
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    Wedges repesent coming out (of the paper), dashes represent going back (into the paper)

    They're the same plane but different diections.
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    (Original post by Superacid)
    So the different type of line (wedged, dotted etc.) actually represents the dimensions rather than the plane ?
    An octahedron is a symmetrical three dimensinal body with eight faces (hence the name) and six apices. You can picture it as two square pyramids fixed base to base.

    The bonds of an octahedral complex lie along the three axes of a three dimensional graph.

    The diagram is meant to represent this. The dotted lines go backwards behind the plane of the paper, the wedges come out towards the viewer in front of the plane of the paper and the other lines lie on the plane of the paper.

    The dotted lines and the wedges lie in the same plane at 90º to the plane of the paper, the xz plane. The paper is the xy plane.



 
 
 
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