The ordering of the Bi vacancies on the primitive lattice lowers the symmetry to Cmmm producing a 6 × 2 × 2 supercell compared to Pm3m, which then is lowered by the octahedral tilting, which has Glazer notation c -b + a -[ESI Video 3] † , to a triclinic cell related to the Pm3m by the following transformative matrix: