“For example, carbon in methane [latex]CH_{4}[/latex] has 4 sigma bonds, and no lone pairs,” Em said, “Thus, the hybrid orbitals of carbon in methane is [latex]s^{1}p^{3}[/latex], or rewriting, [latex]sp^{3}[/latex].”

“Another example, carbon in ethene [latex]C_{2}H_{4}[/latex] has 3 sigma bonds [one bond is a pi bond, which is not counted], and no lone pairs,” Em said, “Thus, the hybrid orbitals of carbon in ethene is, [latex]sp^2[/latex].”

For example, the oxygen in water [latex]\ce{H2O}[/latex] has an [latex]sp^3[/latex] hybrid, but rather than the expected [latex]109.5^{\circ}[/latex], water is bent at a lower angle of [latex]104.5^{\circ}[/latex].

[img]water-angles.png[/img]

Another example, ammonia has a lone pair, and hence rather than the expected [latex]109.5^{\circ}[/latex], has a lower angle of [latex]107.8^{\circ}[/latex].

[img]ammonia-angles.png[/img]

“For example, even though benzene is often drawn theoretically as the first 2, it exists as neither,” Mandy says, “so it is often drawn as the last structure.”

[img]benzene-equilibrium.png[/img]

“For example, benzene has one pi bond from each of the 6 carbons, adding up to 6 pi bonds,” Mandy said, “thereby satisfying Huckel’s rule with [latex]n=1[/latex].”

For example, a structural isomer of pentan-1-ol is pentan-2-ol.