Synthesis, Crystal Structure, and Magnetic Properties of Bi3Mn4O12(NO3) Oxynitrate Comprising S=3/2 Honeycomb Lattice

Neutron diffraction and FT-IR analysis revealed that the novel oxynitrate Bi3Mn4O12(NO3) (space group P3, a = 4.9692(1) angstrom, c = 13.1627(3) angstrom) prepared by hydrothermal synthesis is of a new structural type including flat NO3 layers alternating with blocks of two PbSb2O6-like layers. Mn4+ (S = 3/2) forms a regular honeycomb lattice, and magnetic susceptibility data indicated two-dimensional magnetism. Despite its Weiss constant of -257 K, no long-range ordering was observed down to 0.4 K because of the magnetic frustration due to the competition between the nearest and the next-nearest antiferromagnetic interactions.