Structural Representation of Organic Compounds - JEE PDF Download

Complete Structural Formula

The complete structural formula, often depicted using the Lewis dot structure, provides a comprehensive representation of organic compounds. This method emphasizes the number of bonds formed by each atom in the molecule. Covalent bonds are denoted by dashes (―), with a single dash representing a single bond, a double dash for a double bond, and a triple dash for a triple bond. By illustrating every bond formed between the atoms, the complete structural formula captures the intricate connectivity within the compound.
For example, let's consider three organic compounds: ethane, ethene, and ethyne. The complete structural formulas for these compounds are as follows:

Condensed Structural Formula

In condensed structural formulas, the focus shifts towards simplifying the representation by omitting the individual bonds between carbon atoms. Instead, each distinct structural unit or group is written with subscript numbers indicating multiple substituents, including hydrogen atoms. This condensed form provides a more compact representation while still capturing the essential structural information.

Bond Line Structural Formula

The bond line structural formula is another commonly used method for representing organic compounds. In this approach, bonds are depicted as lines arranged in a zigzag manner. Unless specified, each terminal carbon atom is assumed to have a methyl (-CH3) group attached. This representation streamlines the visual depiction while preserving the connectivity and arrangement of the compound's atoms.

3-D Representation of Organic Compounds

• While the previous representations provided a two-dimensional view of organic compounds, these molecules exist in a three-dimensional space. To accurately depict the 3-D structure, a technique known as wedge-dash representation is employed.
• Wedge-dash representation utilizes various symbols to convey the spatial arrangement of atoms and bonds within the molecule. A solid wedge is used to represent a bond that protrudes out of the plane of the paper, towards the viewer. Conversely, a dashed wedge signifies a bond projecting away from the viewer or into the plane of the paper. Bonds within the plane of the paper are depicted by simple lines.