Fischer Projection

Dhristi JEE 2022-24

What is Fischer Projection?

In Chemistry, molecules exist in a three dimensional plane but to represent them on paper is a daunting task. In 1891, Emil Fischer devised a method by which three dimensional objects could be represented by two dimensional objects by projection. In this article, the definition, convention and uses of a Fischer projection.


Fischer projection is defined as the method of presenting three-dimensional organic molecules in two-dimensional structures on a two-dimensional plane such as a paper. Horizons and vertical lines are used to represent the bonds and the intersection of a horizontal and a vertical line represents the central carbon atom. Isomers of different sugars in organic chemistry are the most common representations of Fischer projection.


There are a few rules to be followed while the Fischer projection is to be used:

  • The carbon atoms in a chain are represented on a vertical line and the non terminal atoms are represented by horizontal and vertical lines. The carbon atoms may not be represented by the letter itself and the intersection of the two lines will depict the carbon atom at the center.

  • All the horizontal lines of  a Fischer projection are projected towards the viewer and all the vertical lines are projected away from the viewers.

  • According to IUPAC rules, all the hydrogen atoms must be drawn explicitly, especially the hydrogen atoms at the end of the group in a carbohydrate.

The Fischer projection looks like a skeletal structure in this regard with the depiction of hydrogen atoms.

Uses and examples

Fischer projections are used to represent molecules and compounds in biochemistry and organic chemistry, especially structures of monosaccharides and amino acids. Since 2006, IUPAC has discouraged representation of amino acids by means of Fischer projection. Monosaccharides have numerous carbon centers with unique bonds on all four sides. Using Fischer projection, the structure of  monosaccharides can be visualized easily.

Apart from showing structures of organic compounds, Fischer projection can also be used to differentiate between L-sugars and D-sugars. L-sugars are depicted by hydrogen atoms on the right and hydroxyl groups on the left, and D-sugars are presented by hydrogen atoms on the left and the hydroxyl groups on the right. 

To learn more about Fischer projection and its properties, applications, and conventions, visit Vedantu's website or download the app where you can get notes, important questions, question papers and a lot more.

More About Fischer Projection

We know that the objects around us are in a three dimensional or 3D state. However, depicting any 3D structure on papers permits two dimensional (2D) representations only. The transition from a 3D state to a 2D state leads to some distortions of the depicted object. Such distortions are typical with chemical molecules in the 3D form, and we have to show them in the 2D state by using some method. The Fischer projection is one of the techniques of showing three-dimensional chemical molecules on paper.

The Fischer projection is a method of representing three-dimensional structures or organic molecules in a two-dimensional setup. Emil Fischer devised the groundbreaking plan in 1891. Horizontal and vertical lines are used to describe the 3D state of the molecules, with the horizontal lines representing attachments pointing out of the papers towards us, and vertical lines representing attachments pointing out the back of the paper, away from us. The intersection of the two lines depicts the central carbon. They are a convenient way to represent chiral molecules and distinguish between pairs of enantiomers. They are most commonly used to show isomers of sugars.

Fischer projections were initially proposed for representing carbohydrates and were used by chemists, particularly in organic chemistry and biochemistry.

Conventions of Fischer Projection

There are specific Fischer projection rules that you must acknowledge before working with the system.

The non-terminal bonds of the molecule are depicted as horizontal and vertical lines. The carbon chain is defined vertically. At times, the carbon atoms may not be shown and represented by the centre of crossing lines.

The orientation of the carbon chain is such that the first carbon (C1) is at the top.

In a Fischer projection, all horizontal bonds are directed towards the viewer. You can easily rotate molecules with a simple tetrahedral geometry in space to meet this condition.

When we use the Fischer projection for a monosaccharide with more than three carbons, there is no way to orient the molecule in space so that all horizontal bonds are slanted towards the viewer.

A Fischer projection is not an accurate representation of the actual 3D configuration of a chemical molecule. It is an altered version of the molecule, ideally twisted at multiple levels along its backbone.

According to IUPAC rules, you must explicitly draw all hydrogen atoms. The hydrogen atoms of the end group of carbohydrates should be particularly present. Hence, in this regard, the Fischer structure is different from skeletal projection.

Thus, it is essential to keep in mind the above mentioned Fischer projection rules before using them practically.

Fischer Projection and Chemical Formula

A fischer projection formula is a convention used to depict a stereo formula in two-dimensional spaces without destroying the stereochemical information, the absolute configurations, at chiral centres.

To convert a stereo formula into a Fischer projection, we can apply the following procedure.

You have to hold the molecule so that the chiral centre is on the plane of the paper. The two bonds coming out of the plane of the paper should be on a horizontal plane. The two remaining bonds going into the plane of the paper are on a vertical plane.

The second step is to push the two bonds coming out of the paper’s plane onto the plane of the paper.

The third step is to pull the two bonds into the paper's plane onto the paper's plane.

Lastly, you should omit the chiral atom symbol for convenience.

Fischer Projection Examples

Fischer projections are generally used for depicting monosaccharide and amino acids. They are suitable for representing monosaccharide because they have numerous stereocenters or carbons with four unique bonds. All monosaccharides are relatively similar and have different orientations along the stereocenter. The Fischer projection enables us to visualize the direction of each monosaccharide easily.

Uses of Fischer Projection

Fischer projections are most commonly used in biochemistry and organic chemistry. You can also use them to show amino acids and other organic molecules, but this is discouraged by IUPAC recommendations since 2006.

You can also use a Fischer projection to differentiate between L-and D- molecules. For example, by definition, in a Fischer projection, the penultimate carbon of D-sugars is depicted with hydrogen on the left and hydroxyl on the right. Likewise, the L sugars will be shown with hydrogen on the right and hydroxyl on the left.

Fischer projections in non-carbohydrates are discouraged; as such, drawings are ambiguous when confused with other types of illustration.


The topic of Fischer projection may seem very tricky to grasp. However, the concept does get manageable with thorough understanding, regularly solving questions and numerical, practising papers and proper revision. Before trying to understand the whole idea, we must learn the basics of the projection and then move to its rules, Fischer projection examples, structure, usage, etc.

Past years' question papers, along with Vedantu's concept pages, are the perfect companions to guide you through the journey of absorbing knowledge. The fun part is that you can access Vedantu's excellent study material and concept pages from the comfort of your home and with the click of a mouse.

FAQs on Fischer Projection

1. What are the Ways to Manipulate Fischer Projection?

As the up and down aspects of the chemical bonds don’t change, a Fischer projection can be rotated by 180 degrees without changing its meaning. Also, a Fischer projection should not be rotated by 90 degrees as such rotation typically alters the configuration to the enantiomer. If you want to find the enantiomer of a molecule depicted as Fischer projection, exchange the right and left horizontal bonds. Lastly, to determine if the molecule in Fischer projection is a meso compound, you can draw a horizontal line through the centre of the molecule and determine whether the molecule is symmetric along that line.

2. How is a Fischer Projection Different From a Haworth Projection of Carbohydrates?

Both Fischer projection and Haworth projections are standard methods of illustrating the stereochemistry of carbohydrates. However, a Haworth projection differs from a Fischer projection as the former is used to represent carbohydrates in their cyclical form. In contrast, the latter is used to depict sugars in their long-chain form.

3. What is the Fischer projection?

Fischer projection is defined as the representation of three dimensional molecules in two dimensional figures on paper by projection without removing stereochemical information at chiral centers. It was devised by Emil Fischer and was mainly used for the depiction of carbohydrates, particularly in organic chemistry.

4. What are the main features of Fischer projection?

The Fischer projection consists of horizontal and vertical lines. The horizontal lines represent atoms that are projected towards the viewer and the vertical lines represent the atoms that are projected away from the viewer. The point of intersections between the horizontal and the vertical lines represent the central carbon atoms.

5. What are some examples of Fischer projection representation?

Fischer projections are generally used to represent compounds in organic chemistry and biochemistry. Monosaccharides and amino acids are most commonly represented by the Fischer projection method in organic chemistry. Monosaccharides have numerous stereochemical centers with carbon atoms and four unique bonds with the carbon atoms. Each center and its projections in a monosaccharide can be visualized easily with the help of the Fischer projection.

6. What is the use of Fischer projection?

Fischer projections can be used to represent chiral molecules and differentiate between pairs of enantiomers in biochemistry and organic chemistry. They can be used to differentiate between L- and D- molecules.

7. What are the limitations of Fischer projection?

There are two limitations of the Fischer projection relating to operations performed on Fischer projection but without changing the absolute configuration at chiral centers. The two limitations can be summed up as follows:

  • Rotating the entire structure by 180° in either direction does not change the absolute configuration.

  • Rotating three ligands on the chiral centers in either direction, does not change the absolute configuration at the center.