Instead of computing BDEs directly using Equation , BDEs can also be calculated using the isodesmic reaction method. An isodesmic reaction is a reaction in which the number of bonds of each bond type is preserved. If an experimental BDE of a reference compound Y-H, BDE(Y-H) exp , is known, one can compute the enthalpy change associated with an isodesmic hydrogen atom transfer (HAT) from a compound of interest X-H to that reference compound Y • , and use it together with BDE(Y-H) exp to obtain the BDE of the bond of interest, BDE(X-H):