Definition of "A" value

1. The conformational preference of an equatorial compared to an axial substituent in a monosubstituted cyclohexane. This steric substituent parameter equals rGo in kcal/mol for the equatorial to axial equilibration on cyclohexane. The values are also known as "Winstein-Holness" A values. HIRSCH (1967); CAREY and SUNDBERG (19