Isomers

Front 1

Constitutional isomers

Back 1

compounds that have the same molecular formula, but with a different order of bonds.

Front 2

Stereo isomers:

Back 2

compounds that have the same molecular formula, and the same order of bonds, but a different orientation in three dimensional space.
We can further organize the different types of stereo isomers into other groups (Enantiomers and Diasteromers)

Front 3

Enantiomers:

Back 3

compounds that have the same molecular formula, same order of bonding, and are non-super imposable mirror images of each other. This means if you take the mirror image of your compound, and can not superimpose the two images, you have a pair of enantiomers. (your hands are the best example of this) Enantiomers are often called optical isomers, because one of the few physical differences in a pair of enantiomers is how they will interact with polarized light. Enantiomers will contain stereo centers (a carbon with 4 different groups attached to it).

Front 4

Diastereomers

Back 4

compounds that have the same molecular formula, same order of bonding, are not mirror images of each other, and are non-super imposable.
There are two common types of diastereomers (Geometric (Trans/Cis), Other)

Front 5

Geometric or cis/trans

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the differences in the three dimensional shape of two molecules are due to a cis/trans relationship between the substituents (this is common in alkenes and cyclic alkanes). To have geometric isomers, you must not have two of the same substituents on one of the carbons in question (for example, a carbon of the double bond).

Front 6

Other

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(still called diastereomers): the differences in the three dimensional shape of the two molecules are due to multiple stereo centers (the conformation of some of which are the same, some of which are different).

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Stereo center

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a carbon with 4 different groups attached to it

Front 8

cis,
trans

Back 8

cis: on the same side
trans: on the opposite side