1. What is Geometrical Isomerism in Symmetrical Molecules?

Definition: Geometrical isomers (or cis-trans isomers) are stereoisomers that occur when you have restricted rotation somewhere in a symmetrical molecule with even-numbered stereocenters.

Purpose: This calculator determines how many distinct geometrical isomers exist for such symmetrical molecules.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( GI_{sym\_ev} \) — Number of geometrical isomers
• \( n_{even} \) — Number of even stereogenic centers (must be ≥ 2 and even)

Explanation: The formula accounts for the symmetrical nature of the molecule and the pairing of stereocenters.

3. Importance of Geometrical Isomer Calculation

Details: Knowing the number of possible isomers helps in predicting molecular properties, reactivity, and biological activity.

4. Using the Calculator

Tips: Enter the number of even stereogenic centers (must be an even number ≥ 2). The calculator will compute the number of possible geometrical isomers.

5. Frequently Asked Questions (FAQ)

Q1: What is a stereogenic center?
A: A stereogenic center is an atom (usually carbon) bearing groups such that interchanging any two groups leads to a stereoisomer.

Q2: Why must the number be even?
A: This formula specifically applies to symmetrical molecules with paired stereocenters.

Q3: What if my molecule has odd stereocenters?
A: Different formulas apply for odd-numbered stereocenters or asymmetrical molecules.

Q4: Does this include all stereoisomers?
A: No, this only counts geometrical (cis-trans) isomers, not other types of stereoisomers.

Q5: Can I use this for cyclic compounds?
A: Yes, if they meet the symmetry and even stereocenter requirements.