How many sigma and pi bonds do sp, sp2, sp3, sp3d, sp3d2 have?
The Correct Answer and Explanation is:
The hybridization of atoms (sp, sp², sp³, sp³d, sp³d²) determines the type and number of sigma (σ) and pi (π) bonds in a molecule. Here’s a breakdown:
- sp hybridization: 1 sigma bond and 2 pi bonds in each triple bond or 1 sigma bond and 1 pi bond in a double bond.
- sp² hybridization: 1 sigma bond and 1 pi bond in each double bond.
- sp³ hybridization: 1 sigma bond with no pi bonds.
- sp³d hybridization: 1 sigma bond in each single bond, usually in a trigonal bipyramidal structure.
- sp³d² hybridization: 1 sigma bond in each single bond, typically in an octahedral structure.
Detailed Explanation
sp Hybridization: In sp hybridization, one s orbital and one p orbital combine, forming two hybrid orbitals. The remaining two unhybridized p orbitals can form two pi bonds. This is typically seen in molecules with triple bonds like ethyne (C≡C). The sigma bond is formed by the overlap of sp orbitals, while the two pi bonds come from the overlap of the unhybridized p orbitals.
sp² Hybridization: In sp² hybridization, one s orbital and two p orbitals combine, forming three sp² hybrid orbitals. One p orbital remains unhybridized, capable of forming one pi bond. A typical example is ethene (C=C), where the sp² orbitals form sigma bonds, and the unhybridized p orbitals form the pi bond.
sp³ Hybridization: In sp³ hybridization, one s orbital and three p orbitals combine to form four sp³ hybrid orbitals. These are used to form sigma bonds only, as in methane (CH₄). Each sp³ orbital forms a sigma bond with other atoms, with no pi bonds involved.
sp³d Hybridization: In sp³d hybridization, one s orbital, three p orbitals, and one d orbital combine to form five hybrid orbitals, which form sigma bonds. This hybridization is seen in trigonal bipyramidal geometries, as in phosphorus pentachloride (PCl₅).
sp³d² Hybridization: In sp³d² hybridization, one s orbital, three p orbitals, and two d orbitals combine to form six hybrid orbitals. This results in sigma bonds in molecules with octahedral geometries, like sulfur hexafluoride (SF₆).
Thus, hybridization determines the arrangement of sigma and pi bonds in a molecule.