Structural Formula: Introduction, Types and Examples

Chemical compounds are made up of atoms that have been bonded together, and we find them all around us- in our food, drinks, and everyday objects. You have probably seen these compounds written in lines with letters, sometimes grouped together, and sometimes with no letters at all, just lines. The formula of a compound can be represented in a variety of ways. In this article, we will learn more about structural formulas, their types, and some examples.

What is a Structural Formula?

The molecular formula tells us how many atoms there are for each element in the compound but not how the elements are bonded together. We don’t know which element’s atom is bonded to which. As a result, the structural formula is critical.

A structural formula depicts how atoms are arranged and bonded together in a chemical compound’s molecular formula.

For instance, consider vinegar and ethyl alcohol compounds and compare their molecular formulas to their structural formulas.

Study About Glucose Chemical Formula Here

We wouldn’t know that acetic acid has a double-bonded carbon atom with oxygen if we didn’t have the structural formula. The structural formula aids in visualising the spatial arrangement of the atoms in the compound.

Structural Formula Types

Sometimes compounds are depicted in lines with letters, sometimes in groups, and sometimes with no letters at all, just lines. Knowing how to “read” these structures will help identify functional groups, draw isomers, name compounds, and so on. There are some common methods for drawing organic compounds. They are as follows:

i. Electron dot structural formula
ii. Expanded structural formula
iii. Condensed structural formula
iv. Bond-line/Skeletal structural formula

Electron Dot Structural Formula

It is the representation that uses dots to represent electrons involved in bonding between different atoms.

For example- the electron dot structural formula of water, ammonia and ethanol are given below:

Expanded Structural Formula

The expanded structural formula illustrates all of the bonds that connect the compound’s atoms.

Condensed Structural Formula

The condensed structural formula still employs lines between bonded atoms, but it is a simpler and shorter way to draw the line-bond structural formula because the carbon and hydrogen bonds are omitted.

A condensed structural formula includes parentheses to show that polyatomic groups within a formula are attached to the next non-hydrogen atom on the left.

For example– The propan\( – 2 – {\text{ol}}\) condensed structural formula can be written as \({\text{C}}{{\text{H}}_3}{\text{CH}}\left({{\text{OH}}} \right){\text{C}}{{\text{H}}_3}.\)

It also employs parentheses to indicate that polyatomic groups are connected to the atom on the right at the start of the formula.

For example– The condensed structural formula of propan\( – 2 – {\text{ol}}\) can also be written as \({\left({{\text{C}}{{\text{H}}_3}} \right)_2}{\text{CHOH}}.\)

Bond-Line/Skeletal Structural Formula

This is the structural formula in its simplest form. It also doesn’t show the \(\left({{\text{C}} – {\text{H}}} \right)\) bonds that hold them together. It only depicts the bond connecting carbon to carbon in the skeleton and the bond(s) connecting other atoms besides hydrogen.