Lewis Structures wedge and dash

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Armo_Derbarsegian_3K
Posts: 35
Joined: Sat Jul 09, 2016 3:00 am

Lewis Structures wedge and dash

Postby Armo_Derbarsegian_3K » Mon Oct 24, 2016 11:59 pm

For example:

SF6's wedge and dash depiction (page 95 of CR) we show the wedges towards us and the dashes away, but we draw lines for on the top and bottom. How do we determine which get wedge and dash, and which get solid lines.

Alternatively, for CH4 how do we determine which get the wedge and dash and which get solid lines...

My issue is determining between wedge and dash and solid lines.

Chem_Mod
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Re: Lewis Structures wedge and dash

Postby Chem_Mod » Tue Oct 25, 2016 12:26 pm

Generally, solid wedges represent groups that are pointing out of the board/page and dashed lines represent groups pointing into the board/page. Groups with bonds represented as lines are pointing in the plane of the board/page. This is just a way of representing 3D shapes in 2D. The wedges and dashes in a trigonal bipyramidal structure are used for "equatorial" groups. This means that for these structures, the wedges and dashes represent groups that are in a plane perpendicular to those groups attached with the "lines" that point up and down in the "axial" position. In a tetrahedral structure like CH4, two groups can be oriented in the plane of the page and have bonds written as lines. One of the other two groups must be oriented so that it points out of the page (solid wedge), and one must be oriented so it points into the page (dashed wedge).


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