(a) Perspective view of the crystal structure of BaMn2(AsO4)2 viewed along the a axis. The quasi-two-dimensional lattice is characterized by [Mn2(AsO4)2]2− slabs, which are highlighted by dark- and light-colored lines representing the Mn—O and As—O bonds, respectively. The wavy and dotted lines (right) indicate the zigzag arrays of barium cations. Only one barium cation with bonds is drawn for clarity, demonstrating the function of Ba—O bonds with regard to holding neighboring [Mn2(AsO4)2]2− slabs. (b) Part of the crystal structure showing corner- and edge-sharing MnO6 octahedra and AsO4 tetrahedra. In each tetramer, the manganese(II) atoms are in a planar configuration related by a center of inversion. (c) Polyhedral representation showing the alternating arrangement of isolated arsenate units. Only two bonds (dotted lines) around barium are shown for clarity.