Builds the three two-f.u. spinel A-site arrangements for six chemistries on the frozen ZnFe2O4 oxygen sublattice and scores them with CHGNet 0.4.2, with regression and shuffle controls.
Foundation models miss the d electrons in spinel site preference
CHGNet and MACE-MP-0 both rank normal spinel arrangements too low in Co, Ni, and Cu ferrites. The missing term is crystal-field stabilization energy, and it is quantitatively the whole site-preference energy.