Materials Data on Ti2NiSe4 by Materials Project
Ti2NiSe4 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Ti3+ is bonded to six Se2- atoms to form TiSe6 octahedra that share corners with six equivalent NiSe6 octahedra, edges with six equivalent TiSe6 octahedra, and a faceface with one NiSe6 octahedra. The corner-sharing octahedra tilt angles range from 48–49°. There are a spread of Ti–Se bond distances ranging from 2.56–2.62 Å. Ni2+ is bonded to six Se2- atoms to form NiSe6 octahedra that share corners with twelve equivalent TiSe6 octahedra, edges with two equivalent NiSe6 octahedra, and faces with two equivalent TiSe6 octahedra. The corner-sharing octahedra tilt angles range from 48–49°. There are two shorter (2.50 Å) and four longer (2.51 Å) Ni–Se bond lengths. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to three equivalent Ti3+ and one Ni2+ atom. In the second Se2- site, Se2- is bonded to three equivalent Ti3+ and two equivalent Ni2+ atoms to form a mixture of distorted edge and corner-sharing SeTi3Ni2 square pyramids.