Materials Data on Co(NiSe2)2 by Materials Project

Abstract

CoNi2Se4 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. Co4+ is bonded to six Se2- atoms to form CoSe6 octahedra that share corners with six equivalent NiSe6 octahedra, edges with two equivalent CoSe6 octahedra, edges with four equivalent NiSe6 octahedra, and a faceface with one NiSe6 octahedra. The corner-sharing octahedra tilt angles range from 49–54°. There are a spread of Co–Se bond distances ranging from 2.36–2.48 Å. There are two inequivalent Ni2+ sites. In the first Ni2+ site, Ni2+ is bonded to six Se2- atoms to form NiSe6 octahedra that share corners with six equivalent CoSe6 octahedra, corners with six equivalent NiSe6 octahedra, edges with two equivalent NiSe6 octahedra, a faceface with one CoSe6 octahedra, and a faceface with one NiSe6 octahedra. The corner-sharing octahedra tilt angles range from 49–54°. There are a spread of Ni–Se bond distances ranging from 2.41–2.51 Å. In the second Ni2+ site, Ni2+ is bonded to six Se2- atoms to form NiSe6 octahedra that share corners with six equivalent NiSe6 octahedra, edges with two equivalent NiSe6 octahedra, edges with four equivalent CoSe6 octahedra, and a faceface with one NiSe6 octahedra. The corner-sharing octahedra tilt angles range from 50–53°. There are a spread of Ni–Se bond distances ranging from 2.38–2.49 Å. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to one Co4+ and three Ni2+ atoms to form distorted SeCoNi3 trigonal pyramids that share corners with three SeCoNi3 trigonal pyramids and edges with two equivalent SeCo2Ni2 trigonal pyramids. In the second Se2- site, Se2- is bonded to two equivalent Co4+ and two Ni2+ atoms to form a mixture of distorted corner and edge-sharing SeCo2Ni2 trigonal pyramids. In the third Se2- site, Se2- is bonded in a 5-coordinate geometry to one Co4+ and four Ni2+ atoms. In the fourth Se2- site, Se2- is bonded in a 5-coordinate geometry to two equivalent Co4+ and three Ni2+ atoms.