eclipsed vs. gauche

[Dr. juju]

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okay just to make sure...
angles between lets say two methyl group on gauche is 60 degrees. for the eclipsed it's 120 degrees (meaning the methyls are further apart).
But eclipsed has a higher potential energy (aka less stable) right?

 

[GRAD]

Just remember that anti>gauche>elcipsed in stability

Anti is when methyls are 180 apart
Gauche is when they're 60 apart,
Eclipsed is when you look at the newman projection and they are right on top of each other.

Check out the Newman projections if you can, or if you have the KAplan book its in there. Eclipsed just means that one methyl is behind another and so if that happens, the energy is really high ( which isnt good)

 

[lifeisgood]

okay just to make sure...
angles between lets say two methyl group on gauche is 60 degrees. for the eclipsed it's 120 degrees (meaning the methyls are further apart).
But eclipsed has a higher potential energy (aka less stable) right?

Assuming we are talking about butane, if the methyls are 120 apart they are NOT eclipsed...the anti config would have the lowest energy, then the gauche, then the eclipsed.