Stereochemistry Flashcards
Isomers
Molecules with the same molecular formula but differ in the way their atoms are arranged.
Two types of isomers
Structural isomers and stereoisomers
Structural isomers
Atoms bonded together in different order
Stereoisomers
Orders is the same but arrangement of atoms is different
Geometric isomerism occurs when…
The molecule cannot be rotated about a point, usually when there is a c=c double bond, and the molecule is symmetrical and there are two different branches on each side.
Can also occur in saturated cycloalkanes
Types of geometric isomers
Trans-(molecule), cis-(molecule)
Trans-(molecule)
On opposite sides of the c=c bond the branches are on different levels.
Cis-(molecule)
On opposite sides of the c=c bond branches are on the same level.
Will two geometric isomers react and behave in the same way?
No they will have different melting and boiling points and can undergo different reactions
What types of carbon compounds can have optical isomers
Chiral carbon compounds
What are optical isomers in relation to one another
Mirror images
Will two optical isomers behave in the same way
Yes except how they react in relation to plane polarised light.
What is plane polarised light?
When the direction of the vibration of the waves of light is same for all waves.
How do two solutions of equal concentrations of optical isomers react to plane polarised light?
One solution will rotate the PPL Ø° the other will rotate the PPL -Ø°
What is a racemic mixture?
A mixture that has an eqiimolar solution of two optical isomers within.
