Chemistry Hybridization: Sigma, Pi Bonds and Sp3

Hybridization in Chemistry

Sigma and Pi Bonds

• Sigma (σ) bonds: formed by head-on overlap of atomic orbitals, resulting in a cylindrical shape
• Pi (π) bonds: formed by lateral overlap of atomic orbitals, resulting in a nodal plane
• Sigma bonds are stronger than pi bonds due to greater orbital overlap
• Multiple bonds (double, triple) contain one sigma bond and one or two pi bonds

Sp3 Hybridization

• Sp3 hybridization occurs when an atom has four electron domains (e.g., methane, CH4)
• The s orbital and three p orbitals mix to form four equivalent hybrid orbitals
• Each sp3 hybrid orbital has 25% s character and 75% p character
• The resulting molecule has a tetrahedral shape

spd, spd2, sp2, and spd3 Hybridization

• spd Hybridization: occurs when an atom has five electron domains (e.g., phosphorus, PF5)
  • The s orbital, three p orbitals, and one d orbital mix to form five hybrid orbitals
  • The resulting molecule has a trigonal bipyramidal shape
• spd2 Hybridization: occurs when an atom has six electron domains (e.g., sulfur, SF6)
  • The s orbital, three p orbitals, and two d orbitals mix to form six hybrid orbitals
  • The resulting molecule has an octahedral shape
• sp2 Hybridization: occurs when an atom has three electron domains (e.g., ethene, C2H4)
  • The s orbital and two p orbitals mix to form three hybrid orbitals
  • The resulting molecule has a trigonal planar shape
• spd3 Hybridization: occurs when an atom has seven electron domains (e.g., iodine, IF7)
  • The s orbital, three p orbitals, and three d orbitals mix to form seven hybrid orbitals
  • The resulting molecule has a pentagonal bipyramidal shape

Sigma and Pi Bonds

• Sigma bonds are formed by head-on overlap of atomic orbitals, resulting in a cylindrical shape
• Pi bonds are formed by lateral overlap of atomic orbitals, resulting in a nodal plane
• Sigma bonds are stronger than pi bonds due to greater orbital overlap
• Multiple bonds (double, triple) contain one sigma bond and one or two pi bonds

Sp3 Hybridization

• Sp3 hybridization occurs when an atom has four electron domains (e.g., methane, CH4)
• The s orbital and three p orbitals mix to form four equivalent hybrid orbitals
• Each sp3 hybrid orbital has 25% s character and 75% p character
• The resulting molecule has a tetrahedral shape

Other Hybridizations

• spd Hybridization: occurs when an atom has five electron domains (e.g., phosphorus, PF5)
• The s orbital, three p orbitals, and one d orbital mix to form five hybrid orbitals
• The resulting molecule has a trigonal bipyramidal shape
• spd2 Hybridization: occurs when an atom has six electron domains (e.g., sulfur, SF6)
• The s orbital, three p orbitals, and two d orbitals mix to form six hybrid orbitals
• The resulting molecule has an octahedral shape
• sp2 Hybridization: occurs when an atom has three electron domains (e.g., ethene, C2H4)
• The s orbital and two p orbitals mix to form three hybrid orbitals
• The resulting molecule has a trigonal planar shape
• spd3 Hybridization: occurs when an atom has seven electron domains (e.g., iodine, IF7)
• The s orbital, three p orbitals, and three d orbitals mix to form seven hybrid orbitals
• The resulting molecule has a pentagonal bipyramidal shape