For part c, I’m just wondering what the preferred structure is for the two options? Do we always prefer the trans isomer of the molecule over the ics isomer because it’s more stable or something?
Textbook 2.59
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Textbook 2.59
For part c, I’m just wondering what the preferred structure is for the two options? Do we always prefer the trans isomer of the molecule over the ics isomer because it’s more stable or something?
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Jayson Hall 2H
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- Joined: Fri Sep 29, 2023 12:13 pm
Re: Textbook 2.59
Hello!
The Lewis structure here is actually deceptive. There is no trans- or cis- isomer for this molecule, CH2Cl2, because this molecule is ALWAYS polar, no matter where the chlorines are placed. The key insight is that CH2Cl2 has a tetrahedral shape. This means that the chlorines CANNOT be on opposite sides of each other because of the way the bond angles / surrounding atoms are arranged in a tetrahedral shape. Additionally, since a tetrahedral shape is symmetric, all possible placements of the chlorine atoms will form an identical looking molecule, just rotated differently (which can be rotated to match the other placements). There will always be a Cl-C-Cl bond angle that is 109.5 degrees. If this still does not make sense, consider finding a 3-D online model of a tetrahedral shape to play with. Hope this helped :)
TLDR: Both Lewis structures are the same in 3D space, so it does not matter which one you use.
The Lewis structure here is actually deceptive. There is no trans- or cis- isomer for this molecule, CH2Cl2, because this molecule is ALWAYS polar, no matter where the chlorines are placed. The key insight is that CH2Cl2 has a tetrahedral shape. This means that the chlorines CANNOT be on opposite sides of each other because of the way the bond angles / surrounding atoms are arranged in a tetrahedral shape. Additionally, since a tetrahedral shape is symmetric, all possible placements of the chlorine atoms will form an identical looking molecule, just rotated differently (which can be rotated to match the other placements). There will always be a Cl-C-Cl bond angle that is 109.5 degrees. If this still does not make sense, consider finding a 3-D online model of a tetrahedral shape to play with. Hope this helped :)
TLDR: Both Lewis structures are the same in 3D space, so it does not matter which one you use.
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