Materials Data on Ti2Cr4(CuSe4)3 by Materials Project

Ti2Cr4(CuSe4)3 is Spinel-derived structured and crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Ti4+ is bonded to six Se2- atoms to form TiSe6 octahedra that share corners with six CuSe4 tetrahedra, an edgeedge with one TiSe6 octahedra, and edges with five CrSe6 octahedra. There are a spread of Ti–Se bond distances ranging from 2.55–2.58 Å. There are three inequivalent Cr3+ sites. In the first Cr3+ site, Cr3+ is bonded to six Se2- atoms to form CrSe6 octahedra that share corners with six CuSe4 tetrahedra, edges with two equivalent TiSe6 octahedra, and edges with four CrSe6 octahedra. There are four shorter (2.53 Å) and two longer (2.54 Å) Cr–Se bond lengths. In the second Cr3+ site, Cr3+ is bonded to six Se2- atoms to form CrSe6 octahedra that share corners with six CuSe4 tetrahedra, edges with three equivalent TiSe6 octahedra, and edges with three CrSe6 octahedra. There are one shorter (2.53 Å) and five longer (2.54 Å) Cr–Se bond lengths. In the third Cr3+ site, Cr3+ is bonded to six Se2- atoms to form CrSe6 octahedra that share corners with six CuSe4 tetrahedra, edges with two equivalent TiSe6 octahedra, and edges with four CrSe6 octahedra. There are two shorter (2.53 Å) and four longer (2.54 Å) Cr–Se bond lengths. There are two inequivalent Cu+1.33+ sites. In the first Cu+1.33+ site, Cu+1.33+ is bonded to four Se2- atoms to form CuSe4 tetrahedra that share corners with four equivalent TiSe6 octahedra and corners with eight CrSe6 octahedra. The corner-sharing octahedra tilt angles range from 56–58°. There are two shorter (2.38 Å) and two longer (2.39 Å) Cu–Se bond lengths. In the second Cu+1.33+ site, Cu+1.33+ is bonded to four Se2- atoms to form CuSe4 tetrahedra that share corners with four equivalent TiSe6 octahedra and corners with eight CrSe6 octahedra. The corner-sharing octahedra tilt angles range from 56–57°. There are two shorter (2.37 Å) and two longer (2.40 Å) Cu–Se bond lengths. There are six inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ti4+, one Cr3+, and one Cu+1.33+ atom. In the second Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to one Ti4+, two Cr3+, and one Cu+1.33+ atom. In the third Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to one Ti4+, two Cr3+, and one Cu+1.33+ atom. In the fourth Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to one Ti4+, two equivalent Cr3+, and one Cu+1.33+ atom. In the fifth Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to one Ti4+, two Cr3+, and one Cu+1.33+ atom. In the sixth Se2- site, Se2- is bonded to three Cr3+ and one Cu+1.33+ atom to form distorted corner-sharing SeCr3Cu trigonal pyramids.