What is the ratio of σ and pi bonds in pyrophosphoric acid ?
Show Hint
In polyatomic structures, count sigma and pi bonds systematically by identifying single and double bonds.
Solution and Explanation
The structure of pyrophosphoric acid (H4P2O7) consists of an O=P-O-P=O backbone with terminal hydroxyl groups (OH).
Step 1: Counting Sigma (\( \sigma \)) Bonds:
- Each single bond (P-O and O-H) is a sigma bond.
- Each double bond (P=O) contains 1 sigma bond.
Total sigma bonds: 12 (8 single P-O and O-H bonds + 4 sigma components from P=O bonds).
Step 2: Counting Pi (\( \pi \)) Bonds:
- Each double bond (P=O) contains 1 pi bond.
Total pi bonds: 2 (from P=O bonds).
Step 3: Ratio of Sigma to Pi Bonds:
\[ \frac{\sigma}{\pi} = \frac{12}{2} = 6 \]
Conclusion:
The ratio of sigma to pi bonds in pyrophosphoric acid is 6:1.
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Concepts Used:
P-Block Elements
- P block elements are those in which the last electron enters any of the three p-orbitals of their respective shells. Since a p-subshell has three degenerate p-orbitals each of which can accommodate two electrons, therefore in all there are six groups of p-block elements.
- P block elements are shiny and usually a good conductor of electricity and heat as they have a tendency to lose an electron. You will find some amazing properties of elements in a P-block element like gallium. It’s a metal that can melt in the palm of your hand. Silicon is also one of the most important metalloids of the p-block group as it is an important component of glass.
P block elements consist of:
- Group 13 Elements: Boron family
- Group 14 Elements: Carbon family
- Group 15 Elements: Nitrogen family
- Group 16 Elements: Oxygen family
- Group 17 Elements: Fluorine family
- Group 18 Elements: Neon family