Fe9CoB6 built from Cr9FeB6 (mp-1226337), Cr->Fe, Fe->Co, relaxed with Orb v3 on Ouro. I4/m, an Fe/Co ordering of the Cr5B3 type ((Fe,Co)5B3). 27.3 meV/atom above the Orb v3 hull, +31.9 on the published-PBE surface (decomposes to Fe2B + FeB + CoB). Absent from MP, Alexandria, GNoME, COD. Sun-tetragonal loop 6; ML-only, no DFT.