Materials Data on MgMo3Se4 by Materials Project
MgMo3Se4 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to five Se2- atoms. There are a spread of Mg–Se bond distances ranging from 2.60–3.26 Å. In the second Mg2+ site, Mg2+ is bonded to six Se2- atoms to form distorted MgSe6 octahedra that share corners with eight MoSe5 square pyramids, edges with four MoSe5 square pyramids, and faces with two MoSe5 square pyramids. There are a spread of Mg–Se bond distances ranging from 2.59–3.15 Å. There are six inequivalent Mo2+ sites. In the first Mo2+ site, Mo2+ is bonded to five Se2- atoms to form MoSe5 square pyramids that share a cornercorner with one MgSe6 octahedra, corners with four MoSe5 square pyramids, edges with five MoSe5 square pyramids, and a faceface with one MgSe6 octahedra. The corner-sharing octahedral tilt angles are 45°. There are a spread of Mo–Se bond distances ranging from 2.60–2.73 Å. In the second Mo2+ site, Mo2+ is bonded to five Se2- atoms to form MoSe5 square pyramids that share corners with four MoSe5 square pyramids, edges with two equivalent MgSe6 octahedra, and edges with five MoSe5 square pyramids. There are a spread of Mo–Se bond distances ranging from 2.59–2.88 Å. In the third Mo2+ site, Mo2+ is bonded to five Se2- atoms to form MoSe5 square pyramids that share corners with three equivalent MgSe6 octahedra, corners with four MoSe5 square pyramids, and edges with five MoSe5 square pyramids. The corner-sharing octahedra tilt angles range from 34–53°. There are a spread of Mo–Se bond distances ranging from 2.58–2.76 Å. In the fourth Mo2+ site, Mo2+ is bonded to five Se2- atoms to form MoSe5 square pyramids that share corners with three equivalent MgSe6 octahedra, corners with four MoSe5 square pyramids, and edges with five MoSe5 square pyramids. The corner-sharing octahedra tilt angles range from 29–47°. There are a spread of Mo–Se bond distances ranging from 2.58–2.75 Å. In the fifth Mo2+ site, Mo2+ is bonded to five Se2- atoms to form MoSe5 square pyramids that share corners with four MoSe5 square pyramids, edges with two equivalent MgSe6 octahedra, and edges with five MoSe5 square pyramids. There are a spread of Mo–Se bond distances ranging from 2.59–2.86 Å. In the sixth Mo2+ site, Mo2+ is bonded to five Se2- atoms to form MoSe5 square pyramids that share a cornercorner with one MgSe6 octahedra, corners with four MoSe5 square pyramids, edges with five MoSe5 square pyramids, and a faceface with one MgSe6 octahedra. The corner-sharing octahedral tilt angles are 59°. There are a spread of Mo–Se bond distances ranging from 2.59–2.77 Å. There are eight inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 5-coordinate geometry to one Mg2+ and four Mo2+ atoms. In the second Se2- site, Se2- is bonded in a 5-coordinate geometry to one Mg2+ and four Mo2+ atoms. In the third Se2- site, Se2- is bonded in a 1-coordinate geometry to two Mg2+ and three Mo2+ atoms. In the fourth Se2- site, Se2- is bonded in a 6-coordinate geometry to two Mg2+ and four Mo2+ atoms. In the fifth Se2- site, Se2- is bonded in a 6-coordinate geometry to two Mg2+ and four Mo2+ atoms. In the sixth Se2- site, Se2- is bonded in a 1-coordinate geometry to one Mg2+ and three Mo2+ atoms. In the seventh Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to four Mo2+ atoms. In the eighth Se2- site, Se2- is bonded in a 1-coordinate geometry to two Mg2+ and four Mo2+ atoms.