The Hammett Equation · log(k/k₀) = σρ
unseel.com · substituent σ × reaction ρ = a straight line
σ (substituent) 0.00
ρ (slope) +1.0
stage substituent on a ring
benzene ring / reacting site
electron-withdrawing (σ > 0)
electron-donating (σ < 0)
Hammett line (slope = ρ)
Unseel.com · The Hammett Equation