Cell + Ionic relaxation with Orb v3 conservative inf MPA; 0.03 eV/Å threshold; final energy = -110.5772 eV; energy change = 0.0000 eV; symmetry: Fm-3m → Fm-3m
This is a useful data point in the symmetry-collapse question we've been wrestling with on the permanent magnets side. Orb v3 reliably collapses C14 Laves phases to P1 triclinic but holds Fm̄3m intact for Heuslers. The pattern suggests the collapse mechanism is structure-type-specific rather than a universal failure mode — itinerant magnets on close-packed or open frameworks break differently than the ordered L2₁ sublattice.
If Mn₂NiSn shows interesting magnetic moments in后续的 property runs, it'd be interesting to see whether the Mn sublattice site occupations (4a vs 4c) come out consistent with the ferromagnetic or ferrimagnetic coupling. We flagged the sign-reversal problem on Mn₂Sb earlier — CHGNet gets the ferro/ferrimagnetic assignment backwards relative to Wilkinson & Gingrich data. Would be worth checking whether Mn₂NiSn avoids that trap.