Materials Data on Mn(BiSe2)2 by Materials Project
MnBi2Se4 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent Mn2+ sites. In the first Mn2+ site, Mn2+ is bonded to six Se2- atoms to form MnSe6 octahedra that share corners with four equivalent BiSe6 octahedra, edges with two equivalent MnSe6 octahedra, and edges with six equivalent BiSe6 octahedra. The corner-sharing octahedral tilt angles are 7°. There are two shorter (2.69 Å) and four longer (2.76 Å) Mn–Se bond lengths. In the second Mn2+ site, Mn2+ is bonded to six Se2- atoms to form MnSe6 octahedra that share corners with two equivalent BiSe6 octahedra and edges with two equivalent MnSe6 octahedra. The corner-sharing octahedral tilt angles are 49°. There are two shorter (2.59 Å) and four longer (2.81 Å) Mn–Se bond lengths. There are two inequivalent Bi3+ sites. In the first Bi3+ site, Bi3+ is bonded to six Se2- atoms to form BiSe6 octahedra that share corners with three MnSe6 octahedra, edges with three equivalent MnSe6 octahedra, and edges with four equivalent BiSe6 octahedra. The corner-sharing octahedra tilt angles range from 7–49°. There are a spread of Bi–Se bond distances ranging from 2.85–3.11 Å. In the second Bi3+ site, Bi3+ is bonded in a 7-coordinate geometry to seven Se2- atoms. There are a spread of Bi–Se bond distances ranging from 2.78–3.59 Å. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to two equivalent Mn2+ and three equivalent Bi3+ atoms to form a mixture of distorted corner and edge-sharing SeMn2Bi3 square pyramids. In the second Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to one Mn2+ and three Bi3+ atoms. In the third Se2- site, Se2- is bonded to two equivalent Mn2+ and three equivalent Bi3+ atoms to form a mixture of corner and edge-sharing SeMn2Bi3 square pyramids. In the fourth Se2- site, Se2- is bonded in a 3-coordinate geometry to one Mn2+ and four Bi3+ atoms.