A 3 dimensional structure is represented in 2 dimensions by using either of the following projection formulas:
1. WEDGE DASH PROJECTION FORMULA
In this projection formula, four bonds of a tetrahedral molecule is shown by two solid lines which represent bonds in the plane, one solid wedge which represent bond up the plane and one broken dash which represent bond down the plane.
2. SAW HORSE PROJECTION FORMULA
(i) These projection formula are obtained by viewing the molecule along the bond joining the two carbon atoms at an oblique angle and projected on the paper.
(ii) The lower left hand carbon is considered to be towards front and upper right hand side carbon towards back.
(iii) The three other atoms/ groups attached to each carbon are represented by 3 lines at an angle of 120°.
3. NEWMAN PROJECTION FORMULA
(i) These projection formulae are obtained by viewing the molecule along the bond joining the two carbon atoms from front C to rear C.
(ii) The front carbon atom is represented by a point and three other atoms/ groups attached to it by 3 equally spaced lines.
(iii) The rear carbon atom is represented by a circle and three atoms / groups attached to it by 3 equally spaced lines.
