Difference between sterioisomers and structural isomers!?

Watch
arvin_infinity
Badges: 3
Rep:
?
#1
Report Thread starter 9 years ago
#1
According to textbook:

Sterioisomer : same structural formula but different 3d arrangement of atoms in space

structural isomer : same molecular forumla but different arrangement of atoms

To me they are identical ! obviously they are not

Please someone explain how they are different!
+rep
0
reply
thegodofgod
Badges: 19
Rep:
?
#2
Report 9 years ago
#2
(Original post by arvin_infinity)
According to textbook:

Sterioisomer : same structural formula but different 3d arrangement of atoms in space

structural isomer : same molecular forumla but different arrangement of atoms

To me they are identical ! obviously they are not

Please someone explain how they are different!
+rep
This sort of explains it well.
1
reply
whotosee
Badges: 1
Rep:
?
#3
Report 9 years ago
#3
You know the difference between structural and molecular formula?
Here's two websites that explain the two things well. Let me know if you don't understand it!

Sterioisomer
http://www.chemguide.co.uk/basicorg/...geometric.html

Structural isomerism
http://www.chemguide.co.uk/basicorg/...tructural.html
0
reply
username890104
Badges: 2
Rep:
?
#4
Report 9 years ago
#4
(Original post by arvin_infinity)
According to textbook:

Sterioisomer : same structural formula but different 3d arrangement of atoms in space

structural isomer : same molecular forumla but different arrangement of atoms

To me they are identical ! obviously they are not

Please someone explain how they are different!
+rep
Structural isomers: same molecular formula, but different structural formulas. You have 3 types of structural isomer; chain, positional and function group.

Structural isomerism deals with the different arrangement of compounds, whereas, stereoisomerism has the same arrangement but a different spacial orientation within the arrangement. That is the difference.

There are 2 types of stereoisomerism; geometric and optical.

Edit: If you need further explanation, then please let me know.
0
reply
arvin_infinity
Badges: 3
Rep:
?
#5
Report Thread starter 9 years ago
#5
(Original post by thegodofgod)
This sort of explains it well.
Like it well answered

(Original post by whotosee)

You know the difference between structural and molecular formula?
Here's two websites that explain the two things well. Let me know if you don't understand it!

(Original post by Tullia)

There are 2 types of stereoisomerism; geometric and optical.

Edit: If you need further explanation, then please let me know.

You have reached the limit of how many posts you can rate today!!!! OH well, will +rep you later


So lets look at this example:


Image

They both have the same molecular formula and same arrangement of atoms and therefore same structural formula

But they have different arrangement of atoms in space
So basically structural is in 2D but sterioisomer is in 3D
0
reply
thegodofgod
Badges: 19
Rep:
?
#6
Report 9 years ago
#6
(Original post by arvin_infinity)
Like it well answered







You have reached the limit of how many posts you can rate today!!!! OH well, will +rep you later


So lets look at this example:


Image

They both have the same molecular formula and same arrangement of atoms and therefore same structural formula

But they have different arrangement of atoms in space
So basically structural is in 2D but sterioisomer is in 3D
Yeh, you could say that, since Optical isomers (a type of stereoisomer) are non-superimposable and are mirror images of each other.
0
reply
Gaz94
Badges: 1
Rep:
?
#7
Report 9 years ago
#7
Structural isomers are compounds with the same molecular formula but a different structural formula.

Stereoisomers are isomers with the same structural formula but with a different arrangement of atoms in space.

E/Z isomerism is an example of steroisomerism in the terms of restricted rotation about a double bond. With the requirement for two different groups to be attached to each Carbon of the C=C group.

Cis/Trans isomerism is a special case of E/Z isomerism where two substituent groups are the same.

Whenever there is E/Z isomerism there is Cis/ Trans they are basically the same thing but E/Z is a more modernly used term.
0
reply
username890104
Badges: 2
Rep:
?
#8
Report 9 years ago
#8
(Original post by arvin_infinity)
So basically structural is in 2D but sterioisomer is in 3D
You seem to have the understanding of the concept, and so it really is thinking of it in a way that works best for you. As far as I can see, there is nothing wrong with thinking about it in that way.

(Original post by Gaz94)
E/Z isomerism is an example of steroisomerism in the terms of restricted rotation about a double bond. With the requirement for two different groups to be attached to each Carbon of the C=C group.

Cis/Trans isomerism is a special case of E/Z isomerism where two substituent groups are the same.

Whenever there is E/Z isomerism there is Cis/ Trans they are basically the same thing but E/Z is a more modernly used term.
It isn't a difficult concept to understand, but it is highly unlikely that anything beyond the cis-trans system will be required for A-level. This is why cis-trans are what are generally taught at A-level.
0
reply
Gaz94
Badges: 1
Rep:
?
#9
Report 9 years ago
#9
(Original post by Tullia)
It isn't a difficult concept to understand, but it is highly unlikely that anything beyond the cis-trans system will be required for A-level. This is why cis-trans are what are generally taught at A-level.
On the OCR F322 specification you mostly need to know E/Z isomerism. Also show examples of Cis/ Trans isomerism. As i said they are the same thing except E/Z is more on the newer specifications.
0
reply
thegodofgod
Badges: 19
Rep:
?
#10
Report 9 years ago
#10
(Original post by Gaz94)
E/Z isomerism is an example of steroisomerism in the terms of restricted rotation about a double bond. With the requirement for two different groups to be attached to each Carbon of the C=C group.

Cis/Trans isomerism is a special case of E/Z isomerism where two substituent groups are the same.

Whenever there is E/Z isomerism there is Cis/ Trans they are basically the same thing but E/Z is a more modernly used term.
I was told that E/Z is the terminology for IUPAC, and Cis/Trans was just old, i.e. they're interchangeable. :confused:
0
reply
Gaz94
Badges: 1
Rep:
?
#11
Report 9 years ago
#11
(Original post by thegodofgod)
I was told that E/Z is the terminology for IUPAC, and Cis/Trans was just old, i.e. they're interchangeable. :confused:
I assume so yes. It's in all my OCR Revision guides and i think it's on the specification sheet. Cis/ Trans is old terminology yes. But E/Z is more of what they are getting towards now i think.

Its because compounds like BromoFluoroChloroEthene can't be named with cis/trans

Instead it is named with E/Z

Such as:

Cis but-2-ene is also pronounces E but-2-ene

E/Z isomerism is an example of steroisomerism in the terms of restricted rotation about a double bond. With the requirement for two different groups to be attached to each Carbon of the C=C group.

E/Z Can have different groups. Cis/trans need 2 substituent groups the same.
0
reply
thegodofgod
Badges: 19
Rep:
?
#12
Report 9 years ago
#12
(Original post by Gaz94)
I assume so yes. It's in all my OCR Revision guides and i think it's on the specification sheet. Cis/ Trans is old terminology yes. But E/Z is more of what they are getting towards now i think.

Such as:

Cis but-2-ene is now E but-2-ene.
Yeah, I get that - I thought you said that there's a difference in the chemistry rather than "Chemistry PCness"
0
reply
Gaz94
Badges: 1
Rep:
?
#13
Report 9 years ago
#13
just edited my post haha read up
0
reply
thegodofgod
Badges: 19
Rep:
?
#14
Report 9 years ago
#14
(Original post by Gaz94)
just edited my post haha read up
ahh - didn't know that :eek:
0
reply
arvin_infinity
Badges: 3
Rep:
?
#15
Report Thread starter 9 years ago
#15
(Original post by thegodofgod)
Yeah, I get that - I thought you said that there's a difference in the chemistry rather than "Chemistry PCness"
Yeh not interchangeable I guess..Basically E/z introduced cuz they couldnt name complicated isomers when all group attached to carbons are different!

So what they do is they look for priorities and then change the complicated version of isomer to a simple version like cis/trans (e.g. higher priorities on different side is E) its beyond A-level to actually identify those priorities
0
reply
username890104
Badges: 2
Rep:
?
#16
Report 9 years ago
#16
(Original post by Gaz94)
I assume so yes. It's in all my OCR Revision guides and i think it's on the specification sheet. Cis/ Trans is old terminology yes. But E/Z is more of what they are getting towards now i think.

Its because compounds like BromoFluoroChloroEthene can't be named with cis/trans

Instead it is named with E/Z

Such as:

Cis but-2-ene is also pronounces E but-2-ene

E/Z isomerism is an example of steroisomerism in the terms of restricted rotation about a double bond. With the requirement for two different groups to be attached to each Carbon of the C=C group.

E/Z Can have different groups. Cis/trans need 2 substituent groups the same.
I know all of this, but didn't realise that you had word perfectly quoted your specification in your original post in this thread. Therefore, I can only apologise for what may have mislead people.

However, in my specification, it is only required to have an appreciation of the E/Z system but not required to be able to apply anything beyond the cis-trans system as molecules of such complexity won't come up in the exam.
0
reply
charco
Badges: 17
Rep:
?
#17
Report 9 years ago
#17
(Original post by arvin_infinity)
Yeh not interchangeable I guess..Basically E/z introduced cuz they couldnt name complicated isomers when all group attached to carbons are different!

So what they do is they look for priorities and then change the complicated version of isomer to a simple version like cis/trans (e.g. higher priorities on different side is E) its beyond A-level to actually identify those priorities
Not beyond A level. It's in the AQA spec...

3.2.9: Students should:
  • know that the alkenes can exhibit E-Z stereoisomerism
  • be able to draw the structures of E and Z isomers
  • understand that E-Z isomers exist due to restricted rotation about the C=C bond


3.4.4: Students should:
  • know and understand the meaning of the term structural isomerism
  • know that E-Z isomerism and optical isomerism are forms of stereoisomerism
0
reply
arvin_infinity
Badges: 3
Rep:
?
#18
Report Thread starter 9 years ago
#18
(Original post by charco)
Not beyond A level. It's in the AQA spec...

3.2.9: Students should:
  • know that the alkenes can exhibit E-Z stereoisomerism
  • be able to draw the structures of E and Z isomers
  • understand that E-Z isomers exist due to restricted rotation about the C=C bond


3.4.4: Students should:
  • know and understand the meaning of the term structural isomerism
  • know that E-Z isomerism and optical isomerism are forms of stereoisomerism
My bad I meant to say its not in the OCR spec!
Dont get me wrong here, e/z is in the OCR spec but identifying them NOT in the syllabus
0
reply
++ben*19++
Badges: 0
Rep:
?
#19
Report 4 years ago
#19
its like if you have C2H2Cl2 you could have CHCl-CHCl or CCl2-CH2 they would be structural isomers
or if you had two molecules both as CHCl-CHCl one could have both Cl on the same side ie: Cl Cl Cl H
C=C OR C=C
H H H Cl

as a result of the double bond the molecules cannot rotate (like Alkanes) so despite having the same structural formula they have a different arrangement of atoms in space therefore it is a stereoisomer
0
reply
alow
Badges: 19
Rep:
?
#20
Report 4 years ago
#20
(Original post by ++ben*19++)
its like if you have C2H2Cl2 you could have CHCl-CHCl or CCl2-CH2 they would be structural isomers
or if you had two molecules both as CHCl-CHCl one could have both Cl on the same side ie: Cl Cl Cl H
C=C OR C=C
H H H Cl

as a result of the double bond the molecules cannot rotate (like Alkanes) so despite having the same structural formula they have a different arrangement of atoms in space therefore it is a stereoisomer
This thread is 5 years old.
1
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Back
to top
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

Do you have the space and resources you need to succeed in home learning?

Yes I have everything I need (325)
56.13%
I don't have everything I need (254)
43.87%

Watched Threads

View All
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise