# steriochemistry 😴

• what is axis of symmetry ?? pls explain eith example ...

• @king-kong Alternate axis of symmetry is the line passing through the molecular structure around which if rotated through an angle X followed by reflection on a mirror placed at right angle to the axis produces the same face of the molecule. To understand lets take an analogy of square. An axis passing through the centre of square and perpendicular to square. If the square is rotated by an angle of 90 degrees, will produce the same face of it in the mirror as that of original. Such an alternating axis will be called C4 axis of symmetry.

Axis of symmetry are called as Cn axis of symmetry, where n is the number obtained by dividing 360 by the angle X.

Now, the organic molecule through which you can imagine to pass an axis about which if the molecule is rotated by an angle of X produces the same face of the molecule as that of original will be said to posses Cx/360 axis of symmetry.

That also means that all molecules posses atleast C1 axis of symmetry.

• @king-kong
It is an imaginary axis around which by rotating through a minimum angle of rotation, the original compound is obtained

• @VIJAY-PREMRAJ-SAINI @jai-d-gr8 but at how muh angle ????means 180 ,360 degree can be minimum angle .....can u show me with a 3d structure

• @king-kong Thank you for the question. This is a simple example and minimum angle of rotation = 360/n
Here n is no. of rotation around the axis. In the diagram after Three rotations of the molecule around the Cn(n=3)/C3 axis through Chlorine(Cl), we get again the original.
So n=3, 360/3 = 120
i.e here minimum angle of rotation is 120. The minimum angle can be different according to the rotation.

• @VIJAY-PREMRAJ-SAINI now i got it thanks 😊