Chapter 2 : Alkanes

When a C atom is attached to 2 groups and so is involved in 2 s bonds, it requires 2 orbitals in the hybrid set. This requires that it is sp hybridised. The general "steps" are similar to that for seen previously sp³ and sp² hybridization.
 

Blend" (i.e. hybridise) the s and a p orbital... since we "mixed" 2 orbitals, we get a set of 2 sp orbitals the other two p orbital remain unaffected both sp hybrids and the 2 p orbitals contain a single unpaired electron

(note the sp hybrids are offset horizontally to allow both lobes to be seen)

In ethyne, HCºCH both C are sp hybridised 2 C-H s bonds are made by the interaction of C sp with H1s orbitals (see red arrows) 1 C-C s bond is made by the interaction of C sp with another C sp orbital (see green arrow) 2 C-C p bonds are made by the interaction of the 2 pairs of C p orbitals (see black arrows)

• sp occurs when a C has 2 attached groups
• sp has 50% s and 50% p character
• the 2 sp hybrids point in opposite directions at 180^o to each other
• each sp hybrid is involved in a s bond
• the remaining p orbitals forms the 2p bonds
• view a triple bond as a s + 2p bonds