Structure Determination of Ferromagnetic Perovskite BiMnO3

Structure of feromagnetic BiMnO3 synthesized at high pressure has been determined by electron diffraction and neutron powder diffraction. This structure is related to a heavily distorted perovskite structure, having monoclinic symmetry, space group C2, with a=9.5323(6) ?, b=5.6064(3) ?, C= 9.8535(7) ?, and =110.667(5)°. The distortion is caused by a polarized Bi 6s2 lone pair. Every trivalent manganese cation reveals the Jahn–Teller distortion and ordering of a vacant dx2-y2 orbital is suggested to play an important role for the ferromagnetism.