The list of STCH oxides contains barium, strontium, and lan-656 thanum manganates, which are previously identified classes of 657 oxides for this application , but also new suggestions like 658 Ba 2 Fe 2 O 5 . On the other hand, it also contains BaMnO 3 , which 659 at first sight appears to be a false-positive, because this oxide 660 is known to reduce too easily and therefore be unable to split 661 water . However, it is just one (mp-19267) out of 9 differ-662 ent BaMnO 3 structures in the MP database, which it is not the 663 ground state. With a ML predicted minimum V O formation en-664 ergy of ∆H d = 3.0 eV it would be a useful water splitter, but the 665 corresponding energy is only 2.2 eV for the BaMnO 3 ground state 666 (mp-1205336) in the MP database, which is too low. Thus, the 667 ML model is consistent with experimental observations, and this 668 example illustrates the tradeoff in choosing the tolerance for the 669 stability criterion. Finally, we note that the list does not contain 670 BCM, an apparent case of a false-negative, resulting from under-671 estimation of the defect energy in the "element-only" encoding 672 used for the MP screening (see Section 2.6). Using the energy 673 from the direct DFT calculation or the "full" encoding ML model, 674 BCM would indeed fall into the STCH process window indicated 675 in Figure .