Chemical Bonding and Molecular Structure

Chemistry · Class 11

Simulation · Chemistry · Class 11

Mixing orbitals into hybrids

From the lesson Hybridisation in Chemical Bonding and Molecular Structure. Change the values and watch what happens.

Mixing orbitals into hybridsChemistry · Class 11

The idea behind it

NCERT § "Hybridisation"

  • Hybridisation is the mixing of atomic orbitals of similar energy on the same atom to form an equal number of equivalent hybrid orbitals.
  • Only orbitals of similar energy hybridise; hybrid orbitals form σ bonds or hold lone pairs, never π bonds.
  • sp: one s + one p, linear, 180°, 50% s character (BeCl₂; each carbon in ethyne).
  • sp²: one s + two p, trigonal planar, 120°, 33% s character (BCl₃; each carbon in ethene).
  • sp³: one s + three p, tetrahedral, 109.5° (109°28′), 25% s character (CH₄); NH₃ and H₂O are also sp³, with angles squeezed by lone pairs.
  • In ethene each carbon uses sp² orbitals for σ bonds and the unhybridised p orbital for the π bond; in ethyne each carbon forms 2 σ bonds and 2 π bonds.
  • sp³d (dz² orbital used) gives a trigonal bipyramid, as in PCl₅; the two axial P–Cl bonds are longer and weaker than the three equatorial bonds, which makes PCl₅ reactive.
  • sp³d² (dz² and dx²−y² used) gives an octahedron, as in SF₆, with six equal S–F bonds at 90°.
  • Quick rule: count σ bonds plus lone pairs on the central atom; 2, 3, 4, 5 and 6 correspond to sp, sp², sp³, sp³d and sp³d².