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| Two-dimensional Conventions |
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| Sawhorse drawings or formulae |
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| In these drawings for ethane, the molecule is viewed slightly from above and from the right and the lower left hand carbon is always considered towards the front. Sawhorse drawings for staggered and eclipsed forms of ethane are shown below: |
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| fig.12.4 - Sawhorse convention for staggered and eclipsed forms of ethane |
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| Newman Projection formulae |
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| The C-C bond is viewed end on. A point represents the near carbon and three lines radiating from this point represent the bonds linking the three other groups attached to this carbon. A circle represents the other carbon atom that is far away and the three bonds attached to this carbon atom are represented by a set of three lines that radiate from the circle. Newman conventions for staggered and eclipsed forms of ethane are shown below: |
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| fig.12.5 - Newman convention for staggered and eclipsed forms of ethane |
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| Between the eclipsed and the staggered forms there is another less stable form called the skew form. Four conformations of 1,2-dichloroethane are given below: |
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| fig.12.6 - Four conformations of 1,2-dichloroethane |
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