IUPAC name

[observer1]

the chemical name of 2,3-dimethyl butane has structure with a ch3 up and down. is it possible for both to be up? what is the name given to that? do the have same/similar properites or different?

[studiot]

https://homework.study.com/explanation/how-many-stereoisomers-of-the-2-3-dimethylbutane-are-possible-a-4-b-none-c-2-d-3.html

[Sensei]

Get ball-n-stick model and build 3D model of this molecule and you should see..

 Every chemistry student should have it.

(I 3D printed my own versions)

 

Edited November 19, 2022 by Sensei

[exchemist]

1 hour ago, observer1 said:

the chemical name of 2,3-dimethyl butane has structure with a ch3 up and down. is it possible for both to be up? what is the name given to that? do the have same/similar properites or different?

They are the same, because rotation around a single bond is possible -  unless there are specific steric hindrances from very large substituents, which a methyl group is not.

Don't forget that the bonds in an sp3 hybridised C atom project in 3D, towards the corners of a tetrahedron. They don't stick out at 90 degrees in a plane, as shown in typical 2D representations like those in your example.

If there were a double bond between C2 and C3 then rotation would not be possible and you could then speak of cis and trans isomers, depending on whether the substituents were on the same side or on opposite sides.

In an sp2 hybridised C. atom, there are 3 bonds at 120degrees to each other in a plane, one or more of the bonds having some double bond character. 

 

Edited November 19, 2022 by exchemist

[studiot]

2 hours ago, exchemist said:

They are the same, because rotation around a single bond is possible -  unless there are specific steric hindrances from very large substituents, which a methyl group is not.

Don't forget that the bonds in an sp3 hybridised C atom project in 3D, towards the corners of a tetrahedron. They don't stick out at 90 degrees in a plane, as shown in typical 2D representations like those in your example.

If there were a double bond between C2 and C3 then rotation would not be possible and you could then speak of cis and trans isomers, depending on whether the substituents were on the same side or on opposite sides.

In an sp2 hybridised C. atom, there are 3 bonds at 120degrees to each other in a plane, one or more of the bonds having some double bond character. 

 

+1