The resulting functional is a 12 parameter spin component scaled double hybrid. Unlike the other functionals we do not re-optimize this functional to work with self-consistent orbitals and use ωB97X orbitals for the final functional. Table shows the coefficients in the ωB97X-MP2-D3(BJ) functional. The weighted RMSEs for this functional for the training and validation sets are 3.58 kcal mol -1 and 2.48 kcal mol -1 respectively. The validation set value is lower than the wRMSE for the initial WM21-D3(BJ) for which the training and validation errors are 3.83 kcal mol -1 and 3.17 kcal mol -1 respectively. However, this is before the parameters are re-optimized for self-consistent orbitals.